diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java
index c1428c1e3..20d06d3d9 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java
@@ -218,14 +218,14 @@ public SubscriberStub getStub() {
    * }
    * </code></pre>
    *
-   * @param name The name of the subscription. It must have the format
+   * @param name Required. The name of the subscription. It must have the format
    *     `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must start with a
    *     letter, and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`), underscores
    *     (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent signs (`%`). It must be between 3
-   *     and 255 characters in length, and it must not start with `"goog"`
-   * @param topic The name of the topic from which this subscription is receiving messages. Format
-   *     is `projects/{project}/topics/{topic}`. The value of this field will be `_deleted-topic_`
-   *     if the topic has been deleted.
+   *     and 255 characters in length, and it must not start with `"goog"`.
+   * @param topic Required. The name of the topic from which this subscription is receiving
+   *     messages. Format is `projects/{project}/topics/{topic}`. The value of this field will be
+   *     `_deleted-topic_` if the topic has been deleted.
    * @param pushConfig If push delivery is used with this subscription, this field is used to
    *     configure it. An empty `pushConfig` signifies that the subscriber will pull and ack
    *     messages using API methods.
@@ -286,14 +286,14 @@ public final Subscription createSubscription(
    * }
    * </code></pre>
    *
-   * @param name The name of the subscription. It must have the format
+   * @param name Required. The name of the subscription. It must have the format
    *     `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must start with a
    *     letter, and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`), underscores
    *     (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent signs (`%`). It must be between 3
-   *     and 255 characters in length, and it must not start with `"goog"`
-   * @param topic The name of the topic from which this subscription is receiving messages. Format
-   *     is `projects/{project}/topics/{topic}`. The value of this field will be `_deleted-topic_`
-   *     if the topic has been deleted.
+   *     and 255 characters in length, and it must not start with `"goog"`.
+   * @param topic Required. The name of the topic from which this subscription is receiving
+   *     messages. Format is `projects/{project}/topics/{topic}`. The value of this field will be
+   *     `_deleted-topic_` if the topic has been deleted.
    * @param pushConfig If push delivery is used with this subscription, this field is used to
    *     configure it. An empty `pushConfig` signifies that the subscriber will pull and ack
    *     messages using API methods.
@@ -406,7 +406,7 @@ public final UnaryCallable<Subscription, Subscription> createSubscriptionCallabl
    * }
    * </code></pre>
    *
-   * @param subscription The name of the subscription to get. Format is
+   * @param subscription Required. The name of the subscription to get. Format is
    *     `projects/{project}/subscriptions/{sub}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -431,7 +431,7 @@ public final Subscription getSubscription(ProjectSubscriptionName subscription)
    * }
    * </code></pre>
    *
-   * @param subscription The name of the subscription to get. Format is
+   * @param subscription Required. The name of the subscription to get. Format is
    *     `projects/{project}/subscriptions/{sub}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -566,7 +566,7 @@ public final UnaryCallable<UpdateSubscriptionRequest, Subscription> updateSubscr
    * }
    * </code></pre>
    *
-   * @param project The name of the project in which to list subscriptions. Format is
+   * @param project Required. The name of the project in which to list subscriptions. Format is
    *     `projects/{project-id}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -593,7 +593,7 @@ public final ListSubscriptionsPagedResponse listSubscriptions(ProjectName projec
    * }
    * </code></pre>
    *
-   * @param project The name of the project in which to list subscriptions. Format is
+   * @param project Required. The name of the project in which to list subscriptions. Format is
    *     `projects/{project-id}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -701,7 +701,7 @@ public final ListSubscriptionsPagedResponse listSubscriptions(ListSubscriptionsR
    * }
    * </code></pre>
    *
-   * @param subscription The subscription to delete. Format is
+   * @param subscription Required. The subscription to delete. Format is
    *     `projects/{project}/subscriptions/{sub}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -729,7 +729,7 @@ public final void deleteSubscription(ProjectSubscriptionName subscription) {
    * }
    * </code></pre>
    *
-   * @param subscription The subscription to delete. Format is
+   * @param subscription Required. The subscription to delete. Format is
    *     `projects/{project}/subscriptions/{sub}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -808,16 +808,16 @@ public final UnaryCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionC
    * }
    * </code></pre>
    *
-   * @param subscription The name of the subscription. Format is
+   * @param subscription Required. The name of the subscription. Format is
    *     `projects/{project}/subscriptions/{sub}`.
-   * @param ackIds List of acknowledgment IDs.
-   * @param ackDeadlineSeconds The new ack deadline with respect to the time this request was sent
-   *     to the Pub/Sub system. For example, if the value is 10, the new ack deadline will expire 10
-   *     seconds after the `ModifyAckDeadline` call was made. Specifying zero might immediately make
-   *     the message available for delivery to another subscriber client. This typically results in
-   *     an increase in the rate of message redeliveries (that is, duplicates). The minimum deadline
-   *     you can specify is 0 seconds. The maximum deadline you can specify is 600 seconds (10
-   *     minutes).
+   * @param ackIds Required. List of acknowledgment IDs.
+   * @param ackDeadlineSeconds Required. The new ack deadline with respect to the time this request
+   *     was sent to the Pub/Sub system. For example, if the value is 10, the new ack deadline will
+   *     expire 10 seconds after the `ModifyAckDeadline` call was made. Specifying zero might
+   *     immediately make the message available for delivery to another subscriber client. This
+   *     typically results in an increase in the rate of message redeliveries (that is, duplicates).
+   *     The minimum deadline you can specify is 0 seconds. The maximum deadline you can specify is
+   *     600 seconds (10 minutes).
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final void modifyAckDeadline(
@@ -849,16 +849,16 @@ public final UnaryCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionC
    * }
    * </code></pre>
    *
-   * @param subscription The name of the subscription. Format is
+   * @param subscription Required. The name of the subscription. Format is
    *     `projects/{project}/subscriptions/{sub}`.
-   * @param ackIds List of acknowledgment IDs.
-   * @param ackDeadlineSeconds The new ack deadline with respect to the time this request was sent
-   *     to the Pub/Sub system. For example, if the value is 10, the new ack deadline will expire 10
-   *     seconds after the `ModifyAckDeadline` call was made. Specifying zero might immediately make
-   *     the message available for delivery to another subscriber client. This typically results in
-   *     an increase in the rate of message redeliveries (that is, duplicates). The minimum deadline
-   *     you can specify is 0 seconds. The maximum deadline you can specify is 600 seconds (10
-   *     minutes).
+   * @param ackIds Required. List of acknowledgment IDs.
+   * @param ackDeadlineSeconds Required. The new ack deadline with respect to the time this request
+   *     was sent to the Pub/Sub system. For example, if the value is 10, the new ack deadline will
+   *     expire 10 seconds after the `ModifyAckDeadline` call was made. Specifying zero might
+   *     immediately make the message available for delivery to another subscriber client. This
+   *     typically results in an increase in the rate of message redeliveries (that is, duplicates).
+   *     The minimum deadline you can specify is 0 seconds. The maximum deadline you can specify is
+   *     600 seconds (10 minutes).
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final void modifyAckDeadline(
@@ -950,10 +950,10 @@ public final UnaryCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionC
    * }
    * </code></pre>
    *
-   * @param subscription The subscription whose message is being acknowledged. Format is
+   * @param subscription Required. The subscription whose message is being acknowledged. Format is
    *     `projects/{project}/subscriptions/{sub}`.
-   * @param ackIds The acknowledgment ID for the messages being acknowledged that was returned by
-   *     the Pub/Sub system in the `Pull` response. Must not be empty.
+   * @param ackIds Required. The acknowledgment ID for the messages being acknowledged that was
+   *     returned by the Pub/Sub system in the `Pull` response. Must not be empty.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final void acknowledge(
@@ -984,10 +984,10 @@ public final UnaryCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionC
    * }
    * </code></pre>
    *
-   * @param subscription The subscription whose message is being acknowledged. Format is
+   * @param subscription Required. The subscription whose message is being acknowledged. Format is
    *     `projects/{project}/subscriptions/{sub}`.
-   * @param ackIds The acknowledgment ID for the messages being acknowledged that was returned by
-   *     the Pub/Sub system in the `Pull` response. Must not be empty.
+   * @param ackIds Required. The acknowledgment ID for the messages being acknowledged that was
+   *     returned by the Pub/Sub system in the `Pull` response. Must not be empty.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final void acknowledge(String subscription, List<String> ackIds) {
@@ -1069,14 +1069,14 @@ public final UnaryCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionC
    * }
    * </code></pre>
    *
-   * @param subscription The subscription from which messages should be pulled. Format is
+   * @param subscription Required. The subscription from which messages should be pulled. Format is
    *     `projects/{project}/subscriptions/{sub}`.
    * @param returnImmediately If this field set to true, the system will respond immediately even if
    *     it there are no messages available to return in the `Pull` response. Otherwise, the system
    *     may wait (for a bounded amount of time) until at least one message is available, rather
    *     than returning no messages.
-   * @param maxMessages The maximum number of messages to return for this request. Must be a
-   *     positive integer. The Pub/Sub system may return fewer than the number specified.
+   * @param maxMessages Required. The maximum number of messages to return for this request. Must be
+   *     a positive integer. The Pub/Sub system may return fewer than the number specified.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final PullResponse pull(
@@ -1106,14 +1106,14 @@ public final UnaryCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionC
    * }
    * </code></pre>
    *
-   * @param subscription The subscription from which messages should be pulled. Format is
+   * @param subscription Required. The subscription from which messages should be pulled. Format is
    *     `projects/{project}/subscriptions/{sub}`.
    * @param returnImmediately If this field set to true, the system will respond immediately even if
    *     it there are no messages available to return in the `Pull` response. Otherwise, the system
    *     may wait (for a bounded amount of time) until at least one message is available, rather
    *     than returning no messages.
-   * @param maxMessages The maximum number of messages to return for this request. Must be a
-   *     positive integer. The Pub/Sub system may return fewer than the number specified.
+   * @param maxMessages Required. The maximum number of messages to return for this request. Must be
+   *     a positive integer. The Pub/Sub system may return fewer than the number specified.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final PullResponse pull(
@@ -1231,9 +1231,9 @@ public final UnaryCallable<DeleteSubscriptionRequest, Empty> deleteSubscriptionC
    * }
    * </code></pre>
    *
-   * @param subscription The name of the subscription. Format is
+   * @param subscription Required. The name of the subscription. Format is
    *     `projects/{project}/subscriptions/{sub}`.
-   * @param pushConfig The push configuration for future deliveries.
+   * @param pushConfig Required. The push configuration for future deliveries.
    *     <p>An empty `pushConfig` indicates that the Pub/Sub system should stop pushing messages
    *     from the given subscription and allow messages to be pulled and acknowledged - effectively
    *     pausing the subscription if `Pull` or `StreamingPull` is not called.
@@ -1267,9 +1267,9 @@ public final void modifyPushConfig(ProjectSubscriptionName subscription, PushCon
    * }
    * </code></pre>
    *
-   * @param subscription The name of the subscription. Format is
+   * @param subscription Required. The name of the subscription. Format is
    *     `projects/{project}/subscriptions/{sub}`.
-   * @param pushConfig The push configuration for future deliveries.
+   * @param pushConfig Required. The push configuration for future deliveries.
    *     <p>An empty `pushConfig` indicates that the Pub/Sub system should stop pushing messages
    *     from the given subscription and allow messages to be pulled and acknowledged - effectively
    *     pausing the subscription if `Pull` or `StreamingPull` is not called.
@@ -1361,7 +1361,7 @@ public final UnaryCallable<ModifyPushConfigRequest, Empty> modifyPushConfigCalla
    * }
    * </code></pre>
    *
-   * @param project The name of the project in which to list snapshots. Format is
+   * @param project Required. The name of the project in which to list snapshots. Format is
    *     `projects/{project-id}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -1391,7 +1391,7 @@ public final ListSnapshotsPagedResponse listSnapshots(ProjectName project) {
    * }
    * </code></pre>
    *
-   * @param project The name of the project in which to list snapshots. Format is
+   * @param project Required. The name of the project in which to list snapshots. Format is
    *     `projects/{project-id}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -1516,17 +1516,18 @@ public final UnaryCallable<ListSnapshotsRequest, ListSnapshotsResponse> listSnap
    * }
    * </code></pre>
    *
-   * @param name User-provided name for this snapshot. If the name is not provided in the request,
-   *     the server will assign a random name for this snapshot on the same project as the
+   * @param name Required. User-provided name for this snapshot. If the name is not provided in the
+   *     request, the server will assign a random name for this snapshot on the same project as the
    *     subscription. Note that for REST API requests, you must specify a name. See the &lt;a
    *     href="https://cloud.google.com/pubsub/docs/admin#resource_names"&gt; resource name
    *     rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
-   * @param subscription The subscription whose backlog the snapshot retains. Specifically, the
-   *     created snapshot is guaranteed to retain: (a) The existing backlog on the subscription.
-   *     More precisely, this is defined as the messages in the subscription's backlog that are
-   *     unacknowledged upon the successful completion of the `CreateSnapshot` request; as well as:
-   *     (b) Any messages published to the subscription's topic following the successful completion
-   *     of the CreateSnapshot request. Format is `projects/{project}/subscriptions/{sub}`.
+   * @param subscription Required. The subscription whose backlog the snapshot retains.
+   *     Specifically, the created snapshot is guaranteed to retain: (a) The existing backlog on the
+   *     subscription. More precisely, this is defined as the messages in the subscription's backlog
+   *     that are unacknowledged upon the successful completion of the `CreateSnapshot` request; as
+   *     well as: (b) Any messages published to the subscription's topic following the successful
+   *     completion of the CreateSnapshot request. Format is
+   *     `projects/{project}/subscriptions/{sub}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   public final Snapshot createSnapshot(
@@ -1565,17 +1566,18 @@ public final Snapshot createSnapshot(
    * }
    * </code></pre>
    *
-   * @param name User-provided name for this snapshot. If the name is not provided in the request,
-   *     the server will assign a random name for this snapshot on the same project as the
+   * @param name Required. User-provided name for this snapshot. If the name is not provided in the
+   *     request, the server will assign a random name for this snapshot on the same project as the
    *     subscription. Note that for REST API requests, you must specify a name. See the &lt;a
    *     href="https://cloud.google.com/pubsub/docs/admin#resource_names"&gt; resource name
    *     rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
-   * @param subscription The subscription whose backlog the snapshot retains. Specifically, the
-   *     created snapshot is guaranteed to retain: (a) The existing backlog on the subscription.
-   *     More precisely, this is defined as the messages in the subscription's backlog that are
-   *     unacknowledged upon the successful completion of the `CreateSnapshot` request; as well as:
-   *     (b) Any messages published to the subscription's topic following the successful completion
-   *     of the CreateSnapshot request. Format is `projects/{project}/subscriptions/{sub}`.
+   * @param subscription Required. The subscription whose backlog the snapshot retains.
+   *     Specifically, the created snapshot is guaranteed to retain: (a) The existing backlog on the
+   *     subscription. More precisely, this is defined as the messages in the subscription's backlog
+   *     that are unacknowledged upon the successful completion of the `CreateSnapshot` request; as
+   *     well as: (b) Any messages published to the subscription's topic following the successful
+   *     completion of the CreateSnapshot request. Format is
+   *     `projects/{project}/subscriptions/{sub}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   public final Snapshot createSnapshot(String name, String subscription) {
@@ -1752,7 +1754,7 @@ public final UnaryCallable<UpdateSnapshotRequest, Snapshot> updateSnapshotCallab
    * }
    * </code></pre>
    *
-   * @param snapshot The name of the snapshot to delete. Format is
+   * @param snapshot Required. The name of the snapshot to delete. Format is
    *     `projects/{project}/snapshots/{snap}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -1784,7 +1786,7 @@ public final void deleteSnapshot(ProjectSnapshotName snapshot) {
    * }
    * </code></pre>
    *
-   * @param snapshot The name of the snapshot to delete. Format is
+   * @param snapshot Required. The name of the snapshot to delete. Format is
    *     `projects/{project}/snapshots/{snap}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -1912,6 +1914,8 @@ public final UnaryCallable<SeekRequest, SeekResponse> seekCallable() {
   /**
    * Sets the access control policy on the specified resource. Replaces any existing policy.
    *
+   * <p>Can return Public Errors: NOT_FOUND, INVALID_ARGUMENT and PERMISSION_DENIED
+   *
    * <p>Sample code:
    *
    * <pre><code>
@@ -1939,6 +1943,8 @@ public final Policy setIamPolicy(String resource, Policy policy) {
   /**
    * Sets the access control policy on the specified resource. Replaces any existing policy.
    *
+   * <p>Can return Public Errors: NOT_FOUND, INVALID_ARGUMENT and PERMISSION_DENIED
+   *
    * <p>Sample code:
    *
    * <pre><code>
@@ -1964,6 +1970,8 @@ public final Policy setIamPolicy(SetIamPolicyRequest request) {
   /**
    * Sets the access control policy on the specified resource. Replaces any existing policy.
    *
+   * <p>Can return Public Errors: NOT_FOUND, INVALID_ARGUMENT and PERMISSION_DENIED
+   *
    * <p>Sample code:
    *
    * <pre><code>
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/TopicAdminClient.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/TopicAdminClient.java
index e95bdeaec..1612e898f 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/TopicAdminClient.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/TopicAdminClient.java
@@ -190,7 +190,7 @@ public PublisherStub getStub() {
    * }
    * </code></pre>
    *
-   * @param name The name of the topic. It must have the format
+   * @param name Required. The name of the topic. It must have the format
    *     `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter, and contain only
    *     letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`),
    *     tildes (`~`), plus (`+`) or percent signs (`%`). It must be between 3 and 255 characters in
@@ -217,7 +217,7 @@ public final Topic createTopic(ProjectTopicName name) {
    * }
    * </code></pre>
    *
-   * @param name The name of the topic. It must have the format
+   * @param name Required. The name of the topic. It must have the format
    *     `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter, and contain only
    *     letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`),
    *     tildes (`~`), plus (`+`) or percent signs (`%`). It must be between 3 and 255 characters in
@@ -345,9 +345,9 @@ public final UnaryCallable<UpdateTopicRequest, Topic> updateTopicCallable() {
    * }
    * </code></pre>
    *
-   * @param topic The messages in the request will be published on this topic. Format is
+   * @param topic Required. The messages in the request will be published on this topic. Format is
    *     `projects/{project}/topics/{topic}`.
-   * @param messages The messages to publish.
+   * @param messages Required. The messages to publish.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final PublishResponse publish(
@@ -378,9 +378,9 @@ public final UnaryCallable<UpdateTopicRequest, Topic> updateTopicCallable() {
    * }
    * </code></pre>
    *
-   * @param topic The messages in the request will be published on this topic. Format is
+   * @param topic Required. The messages in the request will be published on this topic. Format is
    *     `projects/{project}/topics/{topic}`.
-   * @param messages The messages to publish.
+   * @param messages Required. The messages to publish.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   /* package-private */ final PublishResponse publish(String topic, List<PubsubMessage> messages) {
@@ -459,7 +459,8 @@ public final UnaryCallable<UpdateTopicRequest, Topic> updateTopicCallable() {
    * }
    * </code></pre>
    *
-   * @param topic The name of the topic to get. Format is `projects/{project}/topics/{topic}`.
+   * @param topic Required. The name of the topic to get. Format is
+   *     `projects/{project}/topics/{topic}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   public final Topic getTopic(ProjectTopicName topic) {
@@ -481,7 +482,8 @@ public final Topic getTopic(ProjectTopicName topic) {
    * }
    * </code></pre>
    *
-   * @param topic The name of the topic to get. Format is `projects/{project}/topics/{topic}`.
+   * @param topic Required. The name of the topic to get. Format is
+   *     `projects/{project}/topics/{topic}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   public final Topic getTopic(String topic) {
@@ -549,7 +551,7 @@ public final UnaryCallable<GetTopicRequest, Topic> getTopicCallable() {
    * }
    * </code></pre>
    *
-   * @param project The name of the project in which to list topics. Format is
+   * @param project Required. The name of the project in which to list topics. Format is
    *     `projects/{project-id}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -576,7 +578,7 @@ public final ListTopicsPagedResponse listTopics(ProjectName project) {
    * }
    * </code></pre>
    *
-   * @param project The name of the project in which to list topics. Format is
+   * @param project Required. The name of the project in which to list topics. Format is
    *     `projects/{project-id}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -680,7 +682,7 @@ public final UnaryCallable<ListTopicsRequest, ListTopicsResponse> listTopicsCall
    * }
    * </code></pre>
    *
-   * @param topic The name of the topic that subscriptions are attached to. Format is
+   * @param topic Required. The name of the topic that subscriptions are attached to. Format is
    *     `projects/{project}/topics/{topic}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -707,7 +709,7 @@ public final ListTopicSubscriptionsPagedResponse listTopicSubscriptions(ProjectT
    * }
    * </code></pre>
    *
-   * @param topic The name of the topic that subscriptions are attached to. Format is
+   * @param topic Required. The name of the topic that subscriptions are attached to. Format is
    *     `projects/{project}/topics/{topic}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -816,7 +818,8 @@ public final ListTopicSubscriptionsPagedResponse listTopicSubscriptions(
    * }
    * </code></pre>
    *
-   * @param topic Name of the topic to delete. Format is `projects/{project}/topics/{topic}`.
+   * @param topic Required. Name of the topic to delete. Format is
+   *     `projects/{project}/topics/{topic}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   public final void deleteTopic(ProjectTopicName topic) {
@@ -841,7 +844,8 @@ public final void deleteTopic(ProjectTopicName topic) {
    * }
    * </code></pre>
    *
-   * @param topic Name of the topic to delete. Format is `projects/{project}/topics/{topic}`.
+   * @param topic Required. Name of the topic to delete. Format is
+   *     `projects/{project}/topics/{topic}`.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
   public final void deleteTopic(String topic) {
@@ -904,6 +908,8 @@ public final UnaryCallable<DeleteTopicRequest, Empty> deleteTopicCallable() {
   /**
    * Sets the access control policy on the specified resource. Replaces any existing policy.
    *
+   * <p>Can return Public Errors: NOT_FOUND, INVALID_ARGUMENT and PERMISSION_DENIED
+   *
    * <p>Sample code:
    *
    * <pre><code>
@@ -931,6 +937,8 @@ public final Policy setIamPolicy(String resource, Policy policy) {
   /**
    * Sets the access control policy on the specified resource. Replaces any existing policy.
    *
+   * <p>Can return Public Errors: NOT_FOUND, INVALID_ARGUMENT and PERMISSION_DENIED
+   *
    * <p>Sample code:
    *
    * <pre><code>
@@ -956,6 +964,8 @@ public final Policy setIamPolicy(SetIamPolicyRequest request) {
   /**
    * Sets the access control policy on the specified resource. Replaces any existing policy.
    *
+   * <p>Can return Public Errors: NOT_FOUND, INVALID_ARGUMENT and PERMISSION_DENIED
+   *
    * <p>Sample code:
    *
    * <pre><code>
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/package-info.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/package-info.java
index 34f5b032f..1df92ab40 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/package-info.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/package-info.java
@@ -15,7 +15,7 @@
  */
 
 /**
- * A client to Google Cloud Pub/Sub API.
+ * A client to Cloud Pub/Sub API.
  *
  * <p>The interfaces provided are listed below, along with usage samples.
  *
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java
index 20fc4d92c..d3089ca30 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java
@@ -36,7 +36,7 @@
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS
 /**
- * gRPC callable factory implementation for Google Cloud Pub/Sub API.
+ * gRPC callable factory implementation for Cloud Pub/Sub API.
  *
  * <p>This class is for advanced usage.
  */
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java
index 1bf3e90da..f42bb6bce 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java
@@ -52,7 +52,7 @@
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS
 /**
- * gRPC stub implementation for Google Cloud Pub/Sub API.
+ * gRPC stub implementation for Cloud Pub/Sub API.
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java
index e827ead04..8656445c4 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java
@@ -36,7 +36,7 @@
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS
 /**
- * gRPC callable factory implementation for Google Cloud Pub/Sub API.
+ * gRPC callable factory implementation for Cloud Pub/Sub API.
  *
  * <p>This class is for advanced usage.
  */
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java
index 828550c55..5b2310807 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java
@@ -64,7 +64,7 @@
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS
 /**
- * gRPC stub implementation for Google Cloud Pub/Sub API.
+ * gRPC stub implementation for Cloud Pub/Sub API.
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStub.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStub.java
index 6f4905ef1..65956640f 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStub.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/PublisherStub.java
@@ -41,7 +41,7 @@
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS
 /**
- * Base stub class for Google Cloud Pub/Sub API.
+ * Base stub class for Cloud Pub/Sub API.
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStub.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStub.java
index e43a35a63..66f365ee0 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStub.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/stub/SubscriberStub.java
@@ -53,7 +53,7 @@
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS
 /**
- * Base stub class for Google Cloud Pub/Sub API.
+ * Base stub class for Cloud Pub/Sub API.
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequest.java
index 255a051ac..abfe740a5 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequest.java
@@ -132,11 +132,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The subscription whose message is being acknowledged.
+   * Required. The subscription whose message is being acknowledged.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -155,11 +157,13 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The subscription whose message is being acknowledged.
+   * Required. The subscription whose message is being acknowledged.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -181,11 +185,11 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return A list containing the ackIds.
    */
@@ -196,11 +200,11 @@ public com.google.protobuf.ProtocolStringList getAckIdsList() {
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The count of ackIds.
    */
@@ -211,11 +215,11 @@ public int getAckIdsCount() {
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the element to return.
    * @return The ackIds at the given index.
@@ -227,11 +231,11 @@ public java.lang.String getAckIds(int index) {
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the value to return.
    * @return The bytes of the ackIds at the given index.
@@ -596,11 +600,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The subscription whose message is being acknowledged.
+     * Required. The subscription whose message is being acknowledged.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -619,11 +625,13 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The subscription whose message is being acknowledged.
+     * Required. The subscription whose message is being acknowledged.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -642,11 +650,13 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The subscription whose message is being acknowledged.
+     * Required. The subscription whose message is being acknowledged.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -664,11 +674,13 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The subscription whose message is being acknowledged.
+     * Required. The subscription whose message is being acknowledged.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -682,11 +694,13 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The subscription whose message is being acknowledged.
+     * Required. The subscription whose message is being acknowledged.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
@@ -715,11 +729,11 @@ private void ensureAckIdsIsMutable() {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return A list containing the ackIds.
      */
@@ -730,11 +744,11 @@ public com.google.protobuf.ProtocolStringList getAckIdsList() {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The count of ackIds.
      */
@@ -745,11 +759,11 @@ public int getAckIdsCount() {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param index The index of the element to return.
      * @return The ackIds at the given index.
@@ -761,11 +775,11 @@ public java.lang.String getAckIds(int index) {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param index The index of the value to return.
      * @return The bytes of the ackIds at the given index.
@@ -777,11 +791,11 @@ public com.google.protobuf.ByteString getAckIdsBytes(int index) {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param index The index to set the value at.
      * @param value The ackIds to set.
@@ -800,11 +814,11 @@ public Builder setAckIds(int index, java.lang.String value) {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The ackIds to add.
      * @return This builder for chaining.
@@ -822,11 +836,11 @@ public Builder addAckIds(java.lang.String value) {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param values The ackIds to add.
      * @return This builder for chaining.
@@ -841,11 +855,11 @@ public Builder addAllAckIds(java.lang.Iterable<java.lang.String> values) {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return This builder for chaining.
      */
@@ -859,11 +873,11 @@ public Builder clearAckIds() {
      *
      *
      * <pre>
-     * The acknowledgment ID for the messages being acknowledged that was returned
+     * Required. The acknowledgment ID for the messages being acknowledged that was returned
      * by the Pub/Sub system in the `Pull` response. Must not be empty.
      * </pre>
      *
-     * <code>repeated string ack_ids = 2;</code>
+     * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The bytes of the ackIds to add.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequestOrBuilder.java
index ac5b4efdd..294551012 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/AcknowledgeRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface AcknowledgeRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription whose message is being acknowledged.
+   * Required. The subscription whose message is being acknowledged.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -40,11 +42,13 @@ public interface AcknowledgeRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription whose message is being acknowledged.
+   * Required. The subscription whose message is being acknowledged.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -54,11 +58,11 @@ public interface AcknowledgeRequestOrBuilder
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return A list containing the ackIds.
    */
@@ -67,11 +71,11 @@ public interface AcknowledgeRequestOrBuilder
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The count of ackIds.
    */
@@ -80,11 +84,11 @@ public interface AcknowledgeRequestOrBuilder
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the element to return.
    * @return The ackIds at the given index.
@@ -94,11 +98,11 @@ public interface AcknowledgeRequestOrBuilder
    *
    *
    * <pre>
-   * The acknowledgment ID for the messages being acknowledged that was returned
+   * Required. The acknowledgment ID for the messages being acknowledged that was returned
    * by the Pub/Sub system in the `Pull` response. Must not be empty.
    * </pre>
    *
-   * <code>repeated string ack_ids = 2;</code>
+   * <code>repeated string ack_ids = 2 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the value to return.
    * @return The bytes of the ackIds at the given index.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequest.java
index 51c00c2ef..ae660b8f1 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequest.java
@@ -150,7 +150,7 @@ protected com.google.protobuf.MapField internalGetMapField(int number) {
    *
    *
    * <pre>
-   * User-provided name for this snapshot. If the name is not provided in the
+   * Required. User-provided name for this snapshot. If the name is not provided in the
    * request, the server will assign a random name for this snapshot on the same
    * project as the subscription. Note that for REST API requests, you must
    * specify a name.  See the &lt;a
@@ -158,7 +158,9 @@ protected com.google.protobuf.MapField internalGetMapField(int number) {
    * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>
+   * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The name.
    */
@@ -177,7 +179,7 @@ public java.lang.String getName() {
    *
    *
    * <pre>
-   * User-provided name for this snapshot. If the name is not provided in the
+   * Required. User-provided name for this snapshot. If the name is not provided in the
    * request, the server will assign a random name for this snapshot on the same
    * project as the subscription. Note that for REST API requests, you must
    * specify a name.  See the &lt;a
@@ -185,7 +187,9 @@ public java.lang.String getName() {
    * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>
+   * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for name.
    */
@@ -207,7 +211,7 @@ public com.google.protobuf.ByteString getNameBytes() {
    *
    *
    * <pre>
-   * The subscription whose backlog the snapshot retains.
+   * Required. The subscription whose backlog the snapshot retains.
    * Specifically, the created snapshot is guaranteed to retain:
    *  (a) The existing backlog on the subscription. More precisely, this is
    *      defined as the messages in the subscription's backlog that are
@@ -218,7 +222,9 @@ public com.google.protobuf.ByteString getNameBytes() {
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 2;</code>
+   * <code>
+   * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -237,7 +243,7 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The subscription whose backlog the snapshot retains.
+   * Required. The subscription whose backlog the snapshot retains.
    * Specifically, the created snapshot is guaranteed to retain:
    *  (a) The existing backlog on the subscription. More precisely, this is
    *      defined as the messages in the subscription's backlog that are
@@ -248,7 +254,9 @@ public java.lang.String getSubscription() {
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 2;</code>
+   * <code>
+   * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -742,7 +750,7 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * User-provided name for this snapshot. If the name is not provided in the
+     * Required. User-provided name for this snapshot. If the name is not provided in the
      * request, the server will assign a random name for this snapshot on the same
      * project as the subscription. Note that for REST API requests, you must
      * specify a name.  See the &lt;a
@@ -750,7 +758,9 @@ public Builder mergeFrom(
      * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>
+     * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The name.
      */
@@ -769,7 +779,7 @@ public java.lang.String getName() {
      *
      *
      * <pre>
-     * User-provided name for this snapshot. If the name is not provided in the
+     * Required. User-provided name for this snapshot. If the name is not provided in the
      * request, the server will assign a random name for this snapshot on the same
      * project as the subscription. Note that for REST API requests, you must
      * specify a name.  See the &lt;a
@@ -777,7 +787,9 @@ public java.lang.String getName() {
      * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>
+     * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for name.
      */
@@ -796,7 +808,7 @@ public com.google.protobuf.ByteString getNameBytes() {
      *
      *
      * <pre>
-     * User-provided name for this snapshot. If the name is not provided in the
+     * Required. User-provided name for this snapshot. If the name is not provided in the
      * request, the server will assign a random name for this snapshot on the same
      * project as the subscription. Note that for REST API requests, you must
      * specify a name.  See the &lt;a
@@ -804,7 +816,9 @@ public com.google.protobuf.ByteString getNameBytes() {
      * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>
+     * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The name to set.
      * @return This builder for chaining.
@@ -822,7 +836,7 @@ public Builder setName(java.lang.String value) {
      *
      *
      * <pre>
-     * User-provided name for this snapshot. If the name is not provided in the
+     * Required. User-provided name for this snapshot. If the name is not provided in the
      * request, the server will assign a random name for this snapshot on the same
      * project as the subscription. Note that for REST API requests, you must
      * specify a name.  See the &lt;a
@@ -830,7 +844,9 @@ public Builder setName(java.lang.String value) {
      * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>
+     * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -844,7 +860,7 @@ public Builder clearName() {
      *
      *
      * <pre>
-     * User-provided name for this snapshot. If the name is not provided in the
+     * Required. User-provided name for this snapshot. If the name is not provided in the
      * request, the server will assign a random name for this snapshot on the same
      * project as the subscription. Note that for REST API requests, you must
      * specify a name.  See the &lt;a
@@ -852,7 +868,9 @@ public Builder clearName() {
      * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>
+     * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for name to set.
      * @return This builder for chaining.
@@ -873,7 +891,7 @@ public Builder setNameBytes(com.google.protobuf.ByteString value) {
      *
      *
      * <pre>
-     * The subscription whose backlog the snapshot retains.
+     * Required. The subscription whose backlog the snapshot retains.
      * Specifically, the created snapshot is guaranteed to retain:
      *  (a) The existing backlog on the subscription. More precisely, this is
      *      defined as the messages in the subscription's backlog that are
@@ -884,7 +902,9 @@ public Builder setNameBytes(com.google.protobuf.ByteString value) {
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 2;</code>
+     * <code>
+     * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -903,7 +923,7 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The subscription whose backlog the snapshot retains.
+     * Required. The subscription whose backlog the snapshot retains.
      * Specifically, the created snapshot is guaranteed to retain:
      *  (a) The existing backlog on the subscription. More precisely, this is
      *      defined as the messages in the subscription's backlog that are
@@ -914,7 +934,9 @@ public java.lang.String getSubscription() {
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 2;</code>
+     * <code>
+     * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -933,7 +955,7 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The subscription whose backlog the snapshot retains.
+     * Required. The subscription whose backlog the snapshot retains.
      * Specifically, the created snapshot is guaranteed to retain:
      *  (a) The existing backlog on the subscription. More precisely, this is
      *      defined as the messages in the subscription's backlog that are
@@ -944,7 +966,9 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 2;</code>
+     * <code>
+     * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -962,7 +986,7 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The subscription whose backlog the snapshot retains.
+     * Required. The subscription whose backlog the snapshot retains.
      * Specifically, the created snapshot is guaranteed to retain:
      *  (a) The existing backlog on the subscription. More precisely, this is
      *      defined as the messages in the subscription's backlog that are
@@ -973,7 +997,9 @@ public Builder setSubscription(java.lang.String value) {
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 2;</code>
+     * <code>
+     * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -987,7 +1013,7 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The subscription whose backlog the snapshot retains.
+     * Required. The subscription whose backlog the snapshot retains.
      * Specifically, the created snapshot is guaranteed to retain:
      *  (a) The existing backlog on the subscription. More precisely, this is
      *      defined as the messages in the subscription's backlog that are
@@ -998,7 +1024,9 @@ public Builder clearSubscription() {
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 2;</code>
+     * <code>
+     * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequestOrBuilder.java
index f27c2c1c6..ab50a6f1b 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/CreateSnapshotRequestOrBuilder.java
@@ -27,7 +27,7 @@ public interface CreateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * User-provided name for this snapshot. If the name is not provided in the
+   * Required. User-provided name for this snapshot. If the name is not provided in the
    * request, the server will assign a random name for this snapshot on the same
    * project as the subscription. Note that for REST API requests, you must
    * specify a name.  See the &lt;a
@@ -35,7 +35,9 @@ public interface CreateSnapshotRequestOrBuilder
    * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>
+   * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The name.
    */
@@ -44,7 +46,7 @@ public interface CreateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * User-provided name for this snapshot. If the name is not provided in the
+   * Required. User-provided name for this snapshot. If the name is not provided in the
    * request, the server will assign a random name for this snapshot on the same
    * project as the subscription. Note that for REST API requests, you must
    * specify a name.  See the &lt;a
@@ -52,7 +54,9 @@ public interface CreateSnapshotRequestOrBuilder
    * name rules&lt;/a&gt;. Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>
+   * string name = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for name.
    */
@@ -62,7 +66,7 @@ public interface CreateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription whose backlog the snapshot retains.
+   * Required. The subscription whose backlog the snapshot retains.
    * Specifically, the created snapshot is guaranteed to retain:
    *  (a) The existing backlog on the subscription. More precisely, this is
    *      defined as the messages in the subscription's backlog that are
@@ -73,7 +77,9 @@ public interface CreateSnapshotRequestOrBuilder
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 2;</code>
+   * <code>
+   * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -82,7 +88,7 @@ public interface CreateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription whose backlog the snapshot retains.
+   * Required. The subscription whose backlog the snapshot retains.
    * Specifically, the created snapshot is guaranteed to retain:
    *  (a) The existing backlog on the subscription. More precisely, this is
    *      defined as the messages in the subscription's backlog that are
@@ -93,7 +99,9 @@ public interface CreateSnapshotRequestOrBuilder
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 2;</code>
+   * <code>
+   * string subscription = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequest.java
index d10e9b1f6..185507b53 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequest.java
@@ -117,11 +117,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the snapshot to delete.
+   * Required. The name of the snapshot to delete.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The snapshot.
    */
@@ -140,11 +142,13 @@ public java.lang.String getSnapshot() {
    *
    *
    * <pre>
-   * The name of the snapshot to delete.
+   * Required. The name of the snapshot to delete.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for snapshot.
    */
@@ -481,11 +485,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the snapshot to delete.
+     * Required. The name of the snapshot to delete.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The snapshot.
      */
@@ -504,11 +510,13 @@ public java.lang.String getSnapshot() {
      *
      *
      * <pre>
-     * The name of the snapshot to delete.
+     * Required. The name of the snapshot to delete.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for snapshot.
      */
@@ -527,11 +535,13 @@ public com.google.protobuf.ByteString getSnapshotBytes() {
      *
      *
      * <pre>
-     * The name of the snapshot to delete.
+     * Required. The name of the snapshot to delete.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The snapshot to set.
      * @return This builder for chaining.
@@ -549,11 +559,13 @@ public Builder setSnapshot(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the snapshot to delete.
+     * Required. The name of the snapshot to delete.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -567,11 +579,13 @@ public Builder clearSnapshot() {
      *
      *
      * <pre>
-     * The name of the snapshot to delete.
+     * Required. The name of the snapshot to delete.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for snapshot to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequestOrBuilder.java
index 4ae6a394f..43c455746 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSnapshotRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface DeleteSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the snapshot to delete.
+   * Required. The name of the snapshot to delete.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The snapshot.
    */
@@ -40,11 +42,13 @@ public interface DeleteSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the snapshot to delete.
+   * Required. The name of the snapshot to delete.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for snapshot.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequest.java
index dd9a525a0..b488aca0a 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequest.java
@@ -117,11 +117,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The subscription to delete.
+   * Required. The subscription to delete.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -140,11 +142,13 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The subscription to delete.
+   * Required. The subscription to delete.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -481,11 +485,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The subscription to delete.
+     * Required. The subscription to delete.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -504,11 +510,13 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The subscription to delete.
+     * Required. The subscription to delete.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -527,11 +535,13 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The subscription to delete.
+     * Required. The subscription to delete.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -549,11 +559,13 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The subscription to delete.
+     * Required. The subscription to delete.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -567,11 +579,13 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The subscription to delete.
+     * Required. The subscription to delete.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequestOrBuilder.java
index 9bdbad658..d48320804 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteSubscriptionRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface DeleteSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription to delete.
+   * Required. The subscription to delete.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -40,11 +42,13 @@ public interface DeleteSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription to delete.
+   * Required. The subscription to delete.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequest.java
index e9064e512..36056653a 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequest.java
@@ -117,11 +117,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * Name of the topic to delete.
+   * Required. Name of the topic to delete.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -140,11 +142,13 @@ public java.lang.String getTopic() {
    *
    *
    * <pre>
-   * Name of the topic to delete.
+   * Required. Name of the topic to delete.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
@@ -480,11 +484,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * Name of the topic to delete.
+     * Required. Name of the topic to delete.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The topic.
      */
@@ -503,11 +509,13 @@ public java.lang.String getTopic() {
      *
      *
      * <pre>
-     * Name of the topic to delete.
+     * Required. Name of the topic to delete.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for topic.
      */
@@ -526,11 +534,13 @@ public com.google.protobuf.ByteString getTopicBytes() {
      *
      *
      * <pre>
-     * Name of the topic to delete.
+     * Required. Name of the topic to delete.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The topic to set.
      * @return This builder for chaining.
@@ -548,11 +558,13 @@ public Builder setTopic(java.lang.String value) {
      *
      *
      * <pre>
-     * Name of the topic to delete.
+     * Required. Name of the topic to delete.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -566,11 +578,13 @@ public Builder clearTopic() {
      *
      *
      * <pre>
-     * Name of the topic to delete.
+     * Required. Name of the topic to delete.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for topic to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequestOrBuilder.java
index b086d4f1b..a7267ded0 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/DeleteTopicRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface DeleteTopicRequestOrBuilder
    *
    *
    * <pre>
-   * Name of the topic to delete.
+   * Required. Name of the topic to delete.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -40,11 +42,13 @@ public interface DeleteTopicRequestOrBuilder
    *
    *
    * <pre>
-   * Name of the topic to delete.
+   * Required. Name of the topic to delete.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequest.java
index 4ed2639ba..55295c195 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequest.java
@@ -117,11 +117,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the snapshot to get.
+   * Required. The name of the snapshot to get.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The snapshot.
    */
@@ -140,11 +142,13 @@ public java.lang.String getSnapshot() {
    *
    *
    * <pre>
-   * The name of the snapshot to get.
+   * Required. The name of the snapshot to get.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for snapshot.
    */
@@ -480,11 +484,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the snapshot to get.
+     * Required. The name of the snapshot to get.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The snapshot.
      */
@@ -503,11 +509,13 @@ public java.lang.String getSnapshot() {
      *
      *
      * <pre>
-     * The name of the snapshot to get.
+     * Required. The name of the snapshot to get.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for snapshot.
      */
@@ -526,11 +534,13 @@ public com.google.protobuf.ByteString getSnapshotBytes() {
      *
      *
      * <pre>
-     * The name of the snapshot to get.
+     * Required. The name of the snapshot to get.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The snapshot to set.
      * @return This builder for chaining.
@@ -548,11 +558,13 @@ public Builder setSnapshot(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the snapshot to get.
+     * Required. The name of the snapshot to get.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -566,11 +578,13 @@ public Builder clearSnapshot() {
      *
      *
      * <pre>
-     * The name of the snapshot to get.
+     * Required. The name of the snapshot to get.
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 1;</code>
+     * <code>
+     * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for snapshot to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequestOrBuilder.java
index 752610f47..f101510fd 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSnapshotRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface GetSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the snapshot to get.
+   * Required. The name of the snapshot to get.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The snapshot.
    */
@@ -40,11 +42,13 @@ public interface GetSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the snapshot to get.
+   * Required. The name of the snapshot to get.
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 1;</code>
+   * <code>
+   * string snapshot = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for snapshot.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequest.java
index 8c8811027..abca9f36e 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequest.java
@@ -117,11 +117,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the subscription to get.
+   * Required. The name of the subscription to get.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -140,11 +142,13 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The name of the subscription to get.
+   * Required. The name of the subscription to get.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -481,11 +485,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the subscription to get.
+     * Required. The name of the subscription to get.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -504,11 +510,13 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The name of the subscription to get.
+     * Required. The name of the subscription to get.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -527,11 +535,13 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The name of the subscription to get.
+     * Required. The name of the subscription to get.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -549,11 +559,13 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the subscription to get.
+     * Required. The name of the subscription to get.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -567,11 +579,13 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The name of the subscription to get.
+     * Required. The name of the subscription to get.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequestOrBuilder.java
index 44c6441ee..ca8af6c8b 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetSubscriptionRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface GetSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription to get.
+   * Required. The name of the subscription to get.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -40,11 +42,13 @@ public interface GetSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription to get.
+   * Required. The name of the subscription to get.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequest.java
index 916c965b9..8e0f4174d 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequest.java
@@ -117,11 +117,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the topic to get.
+   * Required. The name of the topic to get.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -140,11 +142,13 @@ public java.lang.String getTopic() {
    *
    *
    * <pre>
-   * The name of the topic to get.
+   * Required. The name of the topic to get.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
@@ -478,11 +482,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the topic to get.
+     * Required. The name of the topic to get.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The topic.
      */
@@ -501,11 +507,13 @@ public java.lang.String getTopic() {
      *
      *
      * <pre>
-     * The name of the topic to get.
+     * Required. The name of the topic to get.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for topic.
      */
@@ -524,11 +532,13 @@ public com.google.protobuf.ByteString getTopicBytes() {
      *
      *
      * <pre>
-     * The name of the topic to get.
+     * Required. The name of the topic to get.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The topic to set.
      * @return This builder for chaining.
@@ -546,11 +556,13 @@ public Builder setTopic(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the topic to get.
+     * Required. The name of the topic to get.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -564,11 +576,13 @@ public Builder clearTopic() {
      *
      *
      * <pre>
-     * The name of the topic to get.
+     * Required. The name of the topic to get.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for topic to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequestOrBuilder.java
index 1f8fb5fa0..b3695fc5a 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/GetTopicRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface GetTopicRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the topic to get.
+   * Required. The name of the topic to get.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -40,11 +42,13 @@ public interface GetTopicRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the topic to get.
+   * Required. The name of the topic to get.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequest.java
index cfe49ec73..f3eca13fd 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequest.java
@@ -130,11 +130,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the project in which to list snapshots.
+   * Required. The name of the project in which to list snapshots.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The project.
    */
@@ -153,11 +155,13 @@ public java.lang.String getProject() {
    *
    *
    * <pre>
-   * The name of the project in which to list snapshots.
+   * Required. The name of the project in which to list snapshots.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for project.
    */
@@ -593,11 +597,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the project in which to list snapshots.
+     * Required. The name of the project in which to list snapshots.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The project.
      */
@@ -616,11 +622,13 @@ public java.lang.String getProject() {
      *
      *
      * <pre>
-     * The name of the project in which to list snapshots.
+     * Required. The name of the project in which to list snapshots.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for project.
      */
@@ -639,11 +647,13 @@ public com.google.protobuf.ByteString getProjectBytes() {
      *
      *
      * <pre>
-     * The name of the project in which to list snapshots.
+     * Required. The name of the project in which to list snapshots.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The project to set.
      * @return This builder for chaining.
@@ -661,11 +671,13 @@ public Builder setProject(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the project in which to list snapshots.
+     * Required. The name of the project in which to list snapshots.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -679,11 +691,13 @@ public Builder clearProject() {
      *
      *
      * <pre>
-     * The name of the project in which to list snapshots.
+     * Required. The name of the project in which to list snapshots.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for project to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequestOrBuilder.java
index fa9b053f1..c4a67ace0 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSnapshotsRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface ListSnapshotsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the project in which to list snapshots.
+   * Required. The name of the project in which to list snapshots.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The project.
    */
@@ -40,11 +42,13 @@ public interface ListSnapshotsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the project in which to list snapshots.
+   * Required. The name of the project in which to list snapshots.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for project.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequest.java
index e573ebf23..f1f4b9536 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequest.java
@@ -130,11 +130,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the project in which to list subscriptions.
+   * Required. The name of the project in which to list subscriptions.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The project.
    */
@@ -153,11 +155,13 @@ public java.lang.String getProject() {
    *
    *
    * <pre>
-   * The name of the project in which to list subscriptions.
+   * Required. The name of the project in which to list subscriptions.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for project.
    */
@@ -593,11 +597,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the project in which to list subscriptions.
+     * Required. The name of the project in which to list subscriptions.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The project.
      */
@@ -616,11 +622,13 @@ public java.lang.String getProject() {
      *
      *
      * <pre>
-     * The name of the project in which to list subscriptions.
+     * Required. The name of the project in which to list subscriptions.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for project.
      */
@@ -639,11 +647,13 @@ public com.google.protobuf.ByteString getProjectBytes() {
      *
      *
      * <pre>
-     * The name of the project in which to list subscriptions.
+     * Required. The name of the project in which to list subscriptions.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The project to set.
      * @return This builder for chaining.
@@ -661,11 +671,13 @@ public Builder setProject(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the project in which to list subscriptions.
+     * Required. The name of the project in which to list subscriptions.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -679,11 +691,13 @@ public Builder clearProject() {
      *
      *
      * <pre>
-     * The name of the project in which to list subscriptions.
+     * Required. The name of the project in which to list subscriptions.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for project to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequestOrBuilder.java
index b509d22fb..73b1fac51 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListSubscriptionsRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface ListSubscriptionsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the project in which to list subscriptions.
+   * Required. The name of the project in which to list subscriptions.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The project.
    */
@@ -40,11 +42,13 @@ public interface ListSubscriptionsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the project in which to list subscriptions.
+   * Required. The name of the project in which to list subscriptions.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for project.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequest.java
index 4e1dfb655..80a44a393 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequest.java
@@ -130,11 +130,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the topic that subscriptions are attached to.
+   * Required. The name of the topic that subscriptions are attached to.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -153,11 +155,13 @@ public java.lang.String getTopic() {
    *
    *
    * <pre>
-   * The name of the topic that subscriptions are attached to.
+   * Required. The name of the topic that subscriptions are attached to.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
@@ -595,11 +599,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the topic that subscriptions are attached to.
+     * Required. The name of the topic that subscriptions are attached to.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The topic.
      */
@@ -618,11 +624,13 @@ public java.lang.String getTopic() {
      *
      *
      * <pre>
-     * The name of the topic that subscriptions are attached to.
+     * Required. The name of the topic that subscriptions are attached to.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for topic.
      */
@@ -641,11 +649,13 @@ public com.google.protobuf.ByteString getTopicBytes() {
      *
      *
      * <pre>
-     * The name of the topic that subscriptions are attached to.
+     * Required. The name of the topic that subscriptions are attached to.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The topic to set.
      * @return This builder for chaining.
@@ -663,11 +673,13 @@ public Builder setTopic(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the topic that subscriptions are attached to.
+     * Required. The name of the topic that subscriptions are attached to.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -681,11 +693,13 @@ public Builder clearTopic() {
      *
      *
      * <pre>
-     * The name of the topic that subscriptions are attached to.
+     * Required. The name of the topic that subscriptions are attached to.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for topic to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequestOrBuilder.java
index 4fe1e834c..2d09f8895 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface ListTopicSubscriptionsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the topic that subscriptions are attached to.
+   * Required. The name of the topic that subscriptions are attached to.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -40,11 +42,13 @@ public interface ListTopicSubscriptionsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the topic that subscriptions are attached to.
+   * Required. The name of the topic that subscriptions are attached to.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponse.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponse.java
index 575d2509c..96601b5fd 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponse.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponse.java
@@ -136,7 +136,7 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return A list containing the subscriptions.
    */
@@ -150,7 +150,7 @@ public com.google.protobuf.ProtocolStringList getSubscriptionsList() {
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The count of subscriptions.
    */
@@ -164,7 +164,7 @@ public int getSubscriptionsCount() {
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @param index The index of the element to return.
    * @return The subscriptions at the given index.
@@ -179,7 +179,7 @@ public java.lang.String getSubscriptions(int index) {
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @param index The index of the value to return.
    * @return The bytes of the subscriptions at the given index.
@@ -609,7 +609,7 @@ private void ensureSubscriptionsIsMutable() {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return A list containing the subscriptions.
      */
@@ -623,7 +623,7 @@ public com.google.protobuf.ProtocolStringList getSubscriptionsList() {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return The count of subscriptions.
      */
@@ -637,7 +637,7 @@ public int getSubscriptionsCount() {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param index The index of the element to return.
      * @return The subscriptions at the given index.
@@ -652,7 +652,7 @@ public java.lang.String getSubscriptions(int index) {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param index The index of the value to return.
      * @return The bytes of the subscriptions at the given index.
@@ -667,7 +667,7 @@ public com.google.protobuf.ByteString getSubscriptionsBytes(int index) {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param index The index to set the value at.
      * @param value The subscriptions to set.
@@ -689,7 +689,7 @@ public Builder setSubscriptions(int index, java.lang.String value) {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param value The subscriptions to add.
      * @return This builder for chaining.
@@ -710,7 +710,7 @@ public Builder addSubscriptions(java.lang.String value) {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param values The subscriptions to add.
      * @return This builder for chaining.
@@ -728,7 +728,7 @@ public Builder addAllSubscriptions(java.lang.Iterable<java.lang.String> values)
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return This builder for chaining.
      */
@@ -745,7 +745,7 @@ public Builder clearSubscriptions() {
      * The names of the subscriptions that match the request.
      * </pre>
      *
-     * <code>repeated string subscriptions = 1;</code>
+     * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param value The bytes of the subscriptions to add.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponseOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponseOrBuilder.java
index 0f10a3a1a..265a9dd3a 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponseOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicSubscriptionsResponseOrBuilder.java
@@ -30,7 +30,7 @@ public interface ListTopicSubscriptionsResponseOrBuilder
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return A list containing the subscriptions.
    */
@@ -42,7 +42,7 @@ public interface ListTopicSubscriptionsResponseOrBuilder
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The count of subscriptions.
    */
@@ -54,7 +54,7 @@ public interface ListTopicSubscriptionsResponseOrBuilder
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @param index The index of the element to return.
    * @return The subscriptions at the given index.
@@ -67,7 +67,7 @@ public interface ListTopicSubscriptionsResponseOrBuilder
    * The names of the subscriptions that match the request.
    * </pre>
    *
-   * <code>repeated string subscriptions = 1;</code>
+   * <code>repeated string subscriptions = 1 [(.google.api.resource_reference) = { ... }</code>
    *
    * @param index The index of the value to return.
    * @return The bytes of the subscriptions at the given index.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequest.java
index 598891764..b048fd3de 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequest.java
@@ -130,11 +130,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the project in which to list topics.
+   * Required. The name of the project in which to list topics.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The project.
    */
@@ -153,11 +155,13 @@ public java.lang.String getProject() {
    *
    *
    * <pre>
-   * The name of the project in which to list topics.
+   * Required. The name of the project in which to list topics.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for project.
    */
@@ -592,11 +596,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the project in which to list topics.
+     * Required. The name of the project in which to list topics.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The project.
      */
@@ -615,11 +621,13 @@ public java.lang.String getProject() {
      *
      *
      * <pre>
-     * The name of the project in which to list topics.
+     * Required. The name of the project in which to list topics.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for project.
      */
@@ -638,11 +646,13 @@ public com.google.protobuf.ByteString getProjectBytes() {
      *
      *
      * <pre>
-     * The name of the project in which to list topics.
+     * Required. The name of the project in which to list topics.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The project to set.
      * @return This builder for chaining.
@@ -660,11 +670,13 @@ public Builder setProject(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the project in which to list topics.
+     * Required. The name of the project in which to list topics.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -678,11 +690,13 @@ public Builder clearProject() {
      *
      *
      * <pre>
-     * The name of the project in which to list topics.
+     * Required. The name of the project in which to list topics.
      * Format is `projects/{project-id}`.
      * </pre>
      *
-     * <code>string project = 1;</code>
+     * <code>
+     * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for project to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequestOrBuilder.java
index d50a0a829..8f5219329 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ListTopicsRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface ListTopicsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the project in which to list topics.
+   * Required. The name of the project in which to list topics.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The project.
    */
@@ -40,11 +42,13 @@ public interface ListTopicsRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the project in which to list topics.
+   * Required. The name of the project in which to list topics.
    * Format is `projects/{project-id}`.
    * </pre>
    *
-   * <code>string project = 1;</code>
+   * <code>
+   * string project = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for project.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequest.java
index 241e37892..c2a92e215 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequest.java
@@ -137,11 +137,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -160,11 +162,13 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -186,10 +190,10 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return A list containing the ackIds.
    */
@@ -200,10 +204,10 @@ public com.google.protobuf.ProtocolStringList getAckIdsList() {
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The count of ackIds.
    */
@@ -214,10 +218,10 @@ public int getAckIdsCount() {
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the element to return.
    * @return The ackIds at the given index.
@@ -229,10 +233,10 @@ public java.lang.String getAckIds(int index) {
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the value to return.
    * @return The bytes of the ackIds at the given index.
@@ -247,7 +251,7 @@ public com.google.protobuf.ByteString getAckIdsBytes(int index) {
    *
    *
    * <pre>
-   * The new ack deadline with respect to the time this request was sent to
+   * Required. The new ack deadline with respect to the time this request was sent to
    * the Pub/Sub system. For example, if the value is 10, the new
    * ack deadline will expire 10 seconds after the `ModifyAckDeadline` call
    * was made. Specifying zero might immediately make the message available for
@@ -257,7 +261,7 @@ public com.google.protobuf.ByteString getAckIdsBytes(int index) {
    * The maximum deadline you can specify is 600 seconds (10 minutes).
    * </pre>
    *
-   * <code>int32 ack_deadline_seconds = 3;</code>
+   * <code>int32 ack_deadline_seconds = 3 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The ackDeadlineSeconds.
    */
@@ -637,11 +641,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -660,11 +666,13 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -683,11 +691,13 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -705,11 +715,13 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -723,11 +735,13 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
@@ -756,10 +770,10 @@ private void ensureAckIdsIsMutable() {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return A list containing the ackIds.
      */
@@ -770,10 +784,10 @@ public com.google.protobuf.ProtocolStringList getAckIdsList() {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The count of ackIds.
      */
@@ -784,10 +798,10 @@ public int getAckIdsCount() {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param index The index of the element to return.
      * @return The ackIds at the given index.
@@ -799,10 +813,10 @@ public java.lang.String getAckIds(int index) {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param index The index of the value to return.
      * @return The bytes of the ackIds at the given index.
@@ -814,10 +828,10 @@ public com.google.protobuf.ByteString getAckIdsBytes(int index) {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param index The index to set the value at.
      * @param value The ackIds to set.
@@ -836,10 +850,10 @@ public Builder setAckIds(int index, java.lang.String value) {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The ackIds to add.
      * @return This builder for chaining.
@@ -857,10 +871,10 @@ public Builder addAckIds(java.lang.String value) {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param values The ackIds to add.
      * @return This builder for chaining.
@@ -875,10 +889,10 @@ public Builder addAllAckIds(java.lang.Iterable<java.lang.String> values) {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return This builder for chaining.
      */
@@ -892,10 +906,10 @@ public Builder clearAckIds() {
      *
      *
      * <pre>
-     * List of acknowledgment IDs.
+     * Required. List of acknowledgment IDs.
      * </pre>
      *
-     * <code>repeated string ack_ids = 4;</code>
+     * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The bytes of the ackIds to add.
      * @return This builder for chaining.
@@ -916,7 +930,7 @@ public Builder addAckIdsBytes(com.google.protobuf.ByteString value) {
      *
      *
      * <pre>
-     * The new ack deadline with respect to the time this request was sent to
+     * Required. The new ack deadline with respect to the time this request was sent to
      * the Pub/Sub system. For example, if the value is 10, the new
      * ack deadline will expire 10 seconds after the `ModifyAckDeadline` call
      * was made. Specifying zero might immediately make the message available for
@@ -926,7 +940,7 @@ public Builder addAckIdsBytes(com.google.protobuf.ByteString value) {
      * The maximum deadline you can specify is 600 seconds (10 minutes).
      * </pre>
      *
-     * <code>int32 ack_deadline_seconds = 3;</code>
+     * <code>int32 ack_deadline_seconds = 3 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The ackDeadlineSeconds.
      */
@@ -937,7 +951,7 @@ public int getAckDeadlineSeconds() {
      *
      *
      * <pre>
-     * The new ack deadline with respect to the time this request was sent to
+     * Required. The new ack deadline with respect to the time this request was sent to
      * the Pub/Sub system. For example, if the value is 10, the new
      * ack deadline will expire 10 seconds after the `ModifyAckDeadline` call
      * was made. Specifying zero might immediately make the message available for
@@ -947,7 +961,7 @@ public int getAckDeadlineSeconds() {
      * The maximum deadline you can specify is 600 seconds (10 minutes).
      * </pre>
      *
-     * <code>int32 ack_deadline_seconds = 3;</code>
+     * <code>int32 ack_deadline_seconds = 3 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The ackDeadlineSeconds to set.
      * @return This builder for chaining.
@@ -962,7 +976,7 @@ public Builder setAckDeadlineSeconds(int value) {
      *
      *
      * <pre>
-     * The new ack deadline with respect to the time this request was sent to
+     * Required. The new ack deadline with respect to the time this request was sent to
      * the Pub/Sub system. For example, if the value is 10, the new
      * ack deadline will expire 10 seconds after the `ModifyAckDeadline` call
      * was made. Specifying zero might immediately make the message available for
@@ -972,7 +986,7 @@ public Builder setAckDeadlineSeconds(int value) {
      * The maximum deadline you can specify is 600 seconds (10 minutes).
      * </pre>
      *
-     * <code>int32 ack_deadline_seconds = 3;</code>
+     * <code>int32 ack_deadline_seconds = 3 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return This builder for chaining.
      */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequestOrBuilder.java
index 2c991e59a..eacaf0964 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyAckDeadlineRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface ModifyAckDeadlineRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -40,11 +42,13 @@ public interface ModifyAckDeadlineRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -54,10 +58,10 @@ public interface ModifyAckDeadlineRequestOrBuilder
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return A list containing the ackIds.
    */
@@ -66,10 +70,10 @@ public interface ModifyAckDeadlineRequestOrBuilder
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The count of ackIds.
    */
@@ -78,10 +82,10 @@ public interface ModifyAckDeadlineRequestOrBuilder
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the element to return.
    * @return The ackIds at the given index.
@@ -91,10 +95,10 @@ public interface ModifyAckDeadlineRequestOrBuilder
    *
    *
    * <pre>
-   * List of acknowledgment IDs.
+   * Required. List of acknowledgment IDs.
    * </pre>
    *
-   * <code>repeated string ack_ids = 4;</code>
+   * <code>repeated string ack_ids = 4 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @param index The index of the value to return.
    * @return The bytes of the ackIds at the given index.
@@ -105,7 +109,7 @@ public interface ModifyAckDeadlineRequestOrBuilder
    *
    *
    * <pre>
-   * The new ack deadline with respect to the time this request was sent to
+   * Required. The new ack deadline with respect to the time this request was sent to
    * the Pub/Sub system. For example, if the value is 10, the new
    * ack deadline will expire 10 seconds after the `ModifyAckDeadline` call
    * was made. Specifying zero might immediately make the message available for
@@ -115,7 +119,7 @@ public interface ModifyAckDeadlineRequestOrBuilder
    * The maximum deadline you can specify is 600 seconds (10 minutes).
    * </pre>
    *
-   * <code>int32 ack_deadline_seconds = 3;</code>
+   * <code>int32 ack_deadline_seconds = 3 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The ackDeadlineSeconds.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequest.java
index c3b79e3b6..6b50cb7b9 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequest.java
@@ -132,11 +132,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -155,11 +157,13 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -181,14 +185,15 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
    *
    *
    * <pre>
-   * The push configuration for future deliveries.
+   * Required. The push configuration for future deliveries.
    * An empty `pushConfig` indicates that the Pub/Sub system should
    * stop pushing messages from the given subscription and allow
    * messages to be pulled and acknowledged - effectively pausing
    * the subscription if `Pull` or `StreamingPull` is not called.
    * </pre>
    *
-   * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+   * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the pushConfig field is set.
    */
@@ -199,14 +204,15 @@ public boolean hasPushConfig() {
    *
    *
    * <pre>
-   * The push configuration for future deliveries.
+   * Required. The push configuration for future deliveries.
    * An empty `pushConfig` indicates that the Pub/Sub system should
    * stop pushing messages from the given subscription and allow
    * messages to be pulled and acknowledged - effectively pausing
    * the subscription if `Pull` or `StreamingPull` is not called.
    * </pre>
    *
-   * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+   * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The pushConfig.
    */
@@ -217,14 +223,15 @@ public com.google.pubsub.v1.PushConfig getPushConfig() {
    *
    *
    * <pre>
-   * The push configuration for future deliveries.
+   * Required. The push configuration for future deliveries.
    * An empty `pushConfig` indicates that the Pub/Sub system should
    * stop pushing messages from the given subscription and allow
    * messages to be pulled and acknowledged - effectively pausing
    * the subscription if `Pull` or `StreamingPull` is not called.
    * </pre>
    *
-   * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+   * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public com.google.pubsub.v1.PushConfigOrBuilder getPushConfigOrBuilder() {
     return getPushConfig();
@@ -579,11 +586,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -602,11 +611,13 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -625,11 +636,13 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -647,11 +660,13 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -665,11 +680,13 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The name of the subscription.
+     * Required. The name of the subscription.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
@@ -695,14 +712,15 @@ public Builder setSubscriptionBytes(com.google.protobuf.ByteString value) {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return Whether the pushConfig field is set.
      */
@@ -713,14 +731,15 @@ public boolean hasPushConfig() {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return The pushConfig.
      */
@@ -737,14 +756,15 @@ public com.google.pubsub.v1.PushConfig getPushConfig() {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setPushConfig(com.google.pubsub.v1.PushConfig value) {
       if (pushConfigBuilder_ == null) {
@@ -763,14 +783,15 @@ public Builder setPushConfig(com.google.pubsub.v1.PushConfig value) {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setPushConfig(com.google.pubsub.v1.PushConfig.Builder builderForValue) {
       if (pushConfigBuilder_ == null) {
@@ -786,14 +807,15 @@ public Builder setPushConfig(com.google.pubsub.v1.PushConfig.Builder builderForV
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder mergePushConfig(com.google.pubsub.v1.PushConfig value) {
       if (pushConfigBuilder_ == null) {
@@ -816,14 +838,15 @@ public Builder mergePushConfig(com.google.pubsub.v1.PushConfig value) {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder clearPushConfig() {
       if (pushConfigBuilder_ == null) {
@@ -840,14 +863,15 @@ public Builder clearPushConfig() {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.PushConfig.Builder getPushConfigBuilder() {
 
@@ -858,14 +882,15 @@ public com.google.pubsub.v1.PushConfig.Builder getPushConfigBuilder() {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.PushConfigOrBuilder getPushConfigOrBuilder() {
       if (pushConfigBuilder_ != null) {
@@ -880,14 +905,15 @@ public com.google.pubsub.v1.PushConfigOrBuilder getPushConfigOrBuilder() {
      *
      *
      * <pre>
-     * The push configuration for future deliveries.
+     * Required. The push configuration for future deliveries.
      * An empty `pushConfig` indicates that the Pub/Sub system should
      * stop pushing messages from the given subscription and allow
      * messages to be pulled and acknowledged - effectively pausing
      * the subscription if `Pull` or `StreamingPull` is not called.
      * </pre>
      *
-     * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+     * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.pubsub.v1.PushConfig,
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequestOrBuilder.java
index 97926658c..10a208c31 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/ModifyPushConfigRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface ModifyPushConfigRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -40,11 +42,13 @@ public interface ModifyPushConfigRequestOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription.
+   * Required. The name of the subscription.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -54,14 +58,15 @@ public interface ModifyPushConfigRequestOrBuilder
    *
    *
    * <pre>
-   * The push configuration for future deliveries.
+   * Required. The push configuration for future deliveries.
    * An empty `pushConfig` indicates that the Pub/Sub system should
    * stop pushing messages from the given subscription and allow
    * messages to be pulled and acknowledged - effectively pausing
    * the subscription if `Pull` or `StreamingPull` is not called.
    * </pre>
    *
-   * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+   * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the pushConfig field is set.
    */
@@ -70,14 +75,15 @@ public interface ModifyPushConfigRequestOrBuilder
    *
    *
    * <pre>
-   * The push configuration for future deliveries.
+   * Required. The push configuration for future deliveries.
    * An empty `pushConfig` indicates that the Pub/Sub system should
    * stop pushing messages from the given subscription and allow
    * messages to be pulled and acknowledged - effectively pausing
    * the subscription if `Pull` or `StreamingPull` is not called.
    * </pre>
    *
-   * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+   * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The pushConfig.
    */
@@ -86,14 +92,15 @@ public interface ModifyPushConfigRequestOrBuilder
    *
    *
    * <pre>
-   * The push configuration for future deliveries.
+   * Required. The push configuration for future deliveries.
    * An empty `pushConfig` indicates that the Pub/Sub system should
    * stop pushing messages from the given subscription and allow
    * messages to be pulled and acknowledged - effectively pausing
    * the subscription if `Pull` or `StreamingPull` is not called.
    * </pre>
    *
-   * <code>.google.pubsub.v1.PushConfig push_config = 2;</code>
+   * <code>.google.pubsub.v1.PushConfig push_config = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   com.google.pubsub.v1.PushConfigOrBuilder getPushConfigOrBuilder();
 }
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequest.java
index 6fb2f4378..402948c49 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequest.java
@@ -133,11 +133,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The messages in the request will be published on this topic.
+   * Required. The messages in the request will be published on this topic.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -156,11 +158,13 @@ public java.lang.String getTopic() {
    *
    *
    * <pre>
-   * The messages in the request will be published on this topic.
+   * Required. The messages in the request will be published on this topic.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
@@ -182,10 +186,12 @@ public com.google.protobuf.ByteString getTopicBytes() {
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public java.util.List<com.google.pubsub.v1.PubsubMessage> getMessagesList() {
     return messages_;
@@ -194,10 +200,12 @@ public java.util.List<com.google.pubsub.v1.PubsubMessage> getMessagesList() {
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public java.util.List<? extends com.google.pubsub.v1.PubsubMessageOrBuilder>
       getMessagesOrBuilderList() {
@@ -207,10 +215,12 @@ public java.util.List<com.google.pubsub.v1.PubsubMessage> getMessagesList() {
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public int getMessagesCount() {
     return messages_.size();
@@ -219,10 +229,12 @@ public int getMessagesCount() {
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public com.google.pubsub.v1.PubsubMessage getMessages(int index) {
     return messages_.get(index);
@@ -231,10 +243,12 @@ public com.google.pubsub.v1.PubsubMessage getMessages(int index) {
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public com.google.pubsub.v1.PubsubMessageOrBuilder getMessagesOrBuilder(int index) {
     return messages_.get(index);
@@ -616,11 +630,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The messages in the request will be published on this topic.
+     * Required. The messages in the request will be published on this topic.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The topic.
      */
@@ -639,11 +655,13 @@ public java.lang.String getTopic() {
      *
      *
      * <pre>
-     * The messages in the request will be published on this topic.
+     * Required. The messages in the request will be published on this topic.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for topic.
      */
@@ -662,11 +680,13 @@ public com.google.protobuf.ByteString getTopicBytes() {
      *
      *
      * <pre>
-     * The messages in the request will be published on this topic.
+     * Required. The messages in the request will be published on this topic.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The topic to set.
      * @return This builder for chaining.
@@ -684,11 +704,13 @@ public Builder setTopic(java.lang.String value) {
      *
      *
      * <pre>
-     * The messages in the request will be published on this topic.
+     * Required. The messages in the request will be published on this topic.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -702,11 +724,13 @@ public Builder clearTopic() {
      *
      *
      * <pre>
-     * The messages in the request will be published on this topic.
+     * Required. The messages in the request will be published on this topic.
      * Format is `projects/{project}/topics/{topic}`.
      * </pre>
      *
-     * <code>string topic = 1;</code>
+     * <code>
+     * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for topic to set.
      * @return This builder for chaining.
@@ -742,10 +766,12 @@ private void ensureMessagesIsMutable() {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public java.util.List<com.google.pubsub.v1.PubsubMessage> getMessagesList() {
       if (messagesBuilder_ == null) {
@@ -758,10 +784,12 @@ public java.util.List<com.google.pubsub.v1.PubsubMessage> getMessagesList() {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public int getMessagesCount() {
       if (messagesBuilder_ == null) {
@@ -774,10 +802,12 @@ public int getMessagesCount() {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.PubsubMessage getMessages(int index) {
       if (messagesBuilder_ == null) {
@@ -790,10 +820,12 @@ public com.google.pubsub.v1.PubsubMessage getMessages(int index) {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setMessages(int index, com.google.pubsub.v1.PubsubMessage value) {
       if (messagesBuilder_ == null) {
@@ -812,10 +844,12 @@ public Builder setMessages(int index, com.google.pubsub.v1.PubsubMessage value)
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setMessages(
         int index, com.google.pubsub.v1.PubsubMessage.Builder builderForValue) {
@@ -832,10 +866,12 @@ public Builder setMessages(
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder addMessages(com.google.pubsub.v1.PubsubMessage value) {
       if (messagesBuilder_ == null) {
@@ -854,10 +890,12 @@ public Builder addMessages(com.google.pubsub.v1.PubsubMessage value) {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder addMessages(int index, com.google.pubsub.v1.PubsubMessage value) {
       if (messagesBuilder_ == null) {
@@ -876,10 +914,12 @@ public Builder addMessages(int index, com.google.pubsub.v1.PubsubMessage value)
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder addMessages(com.google.pubsub.v1.PubsubMessage.Builder builderForValue) {
       if (messagesBuilder_ == null) {
@@ -895,10 +935,12 @@ public Builder addMessages(com.google.pubsub.v1.PubsubMessage.Builder builderFor
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder addMessages(
         int index, com.google.pubsub.v1.PubsubMessage.Builder builderForValue) {
@@ -915,10 +957,12 @@ public Builder addMessages(
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder addAllMessages(
         java.lang.Iterable<? extends com.google.pubsub.v1.PubsubMessage> values) {
@@ -935,10 +979,12 @@ public Builder addAllMessages(
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder clearMessages() {
       if (messagesBuilder_ == null) {
@@ -954,10 +1000,12 @@ public Builder clearMessages() {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder removeMessages(int index) {
       if (messagesBuilder_ == null) {
@@ -973,10 +1021,12 @@ public Builder removeMessages(int index) {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.PubsubMessage.Builder getMessagesBuilder(int index) {
       return getMessagesFieldBuilder().getBuilder(index);
@@ -985,10 +1035,12 @@ public com.google.pubsub.v1.PubsubMessage.Builder getMessagesBuilder(int index)
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.PubsubMessageOrBuilder getMessagesOrBuilder(int index) {
       if (messagesBuilder_ == null) {
@@ -1001,10 +1053,12 @@ public com.google.pubsub.v1.PubsubMessageOrBuilder getMessagesOrBuilder(int inde
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public java.util.List<? extends com.google.pubsub.v1.PubsubMessageOrBuilder>
         getMessagesOrBuilderList() {
@@ -1018,10 +1072,12 @@ public com.google.pubsub.v1.PubsubMessageOrBuilder getMessagesOrBuilder(int inde
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.PubsubMessage.Builder addMessagesBuilder() {
       return getMessagesFieldBuilder()
@@ -1031,10 +1087,12 @@ public com.google.pubsub.v1.PubsubMessage.Builder addMessagesBuilder() {
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.PubsubMessage.Builder addMessagesBuilder(int index) {
       return getMessagesFieldBuilder()
@@ -1044,10 +1102,12 @@ public com.google.pubsub.v1.PubsubMessage.Builder addMessagesBuilder(int index)
      *
      *
      * <pre>
-     * The messages to publish.
+     * Required. The messages to publish.
      * </pre>
      *
-     * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+     * <code>
+     * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public java.util.List<com.google.pubsub.v1.PubsubMessage.Builder> getMessagesBuilderList() {
       return getMessagesFieldBuilder().getBuilderList();
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequestOrBuilder.java
index 9b4e97707..d233bca82 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PublishRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface PublishRequestOrBuilder
    *
    *
    * <pre>
-   * The messages in the request will be published on this topic.
+   * Required. The messages in the request will be published on this topic.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -40,11 +42,13 @@ public interface PublishRequestOrBuilder
    *
    *
    * <pre>
-   * The messages in the request will be published on this topic.
+   * Required. The messages in the request will be published on this topic.
    * Format is `projects/{project}/topics/{topic}`.
    * </pre>
    *
-   * <code>string topic = 1;</code>
+   * <code>
+   * string topic = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
@@ -54,50 +58,60 @@ public interface PublishRequestOrBuilder
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   java.util.List<com.google.pubsub.v1.PubsubMessage> getMessagesList();
   /**
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   com.google.pubsub.v1.PubsubMessage getMessages(int index);
   /**
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   int getMessagesCount();
   /**
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   java.util.List<? extends com.google.pubsub.v1.PubsubMessageOrBuilder> getMessagesOrBuilderList();
   /**
    *
    *
    * <pre>
-   * The messages to publish.
+   * Required. The messages to publish.
    * </pre>
    *
-   * <code>repeated .google.pubsub.v1.PubsubMessage messages = 2;</code>
+   * <code>
+   * repeated .google.pubsub.v1.PubsubMessage messages = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   com.google.pubsub.v1.PubsubMessageOrBuilder getMessagesOrBuilder(int index);
 }
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PubsubProto.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PubsubProto.java
index 929f6ad56..9320aa828 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PubsubProto.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PubsubProto.java
@@ -225,226 +225,271 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
   static {
     java.lang.String[] descriptorData = {
       "\n\035google/pubsub/v1/pubsub.proto\022\020google."
-          + "pubsub.v1\032\034google/api/annotations.proto\032"
-          + "\027google/api/client.proto\032\036google/protobu"
-          + "f/duration.proto\032\033google/protobuf/empty."
-          + "proto\032 google/protobuf/field_mask.proto\032"
-          + "\037google/protobuf/timestamp.proto\";\n\024Mess"
-          + "ageStoragePolicy\022#\n\033allowed_persistence_"
-          + "regions\030\001 \003(\t\"\327\001\n\005Topic\022\014\n\004name\030\001 \001(\t\0223\n"
-          + "\006labels\030\002 \003(\0132#.google.pubsub.v1.Topic.L"
-          + "abelsEntry\022F\n\026message_storage_policy\030\003 \001"
-          + "(\0132&.google.pubsub.v1.MessageStoragePoli"
-          + "cy\022\024\n\014kms_key_name\030\005 \001(\t\032-\n\013LabelsEntry\022"
-          + "\013\n\003key\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\0028\001\"\361\001\n\rPubs"
-          + "ubMessage\022\014\n\004data\030\001 \001(\014\022C\n\nattributes\030\002 "
-          + "\003(\0132/.google.pubsub.v1.PubsubMessage.Att"
-          + "ributesEntry\022\022\n\nmessage_id\030\003 \001(\t\0220\n\014publ"
-          + "ish_time\030\004 \001(\0132\032.google.protobuf.Timesta"
-          + "mp\022\024\n\014ordering_key\030\005 \001(\t\0321\n\017AttributesEn"
-          + "try\022\013\n\003key\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\0028\001\" \n\017G"
-          + "etTopicRequest\022\r\n\005topic\030\001 \001(\t\"m\n\022UpdateT"
-          + "opicRequest\022&\n\005topic\030\001 \001(\0132\027.google.pubs"
-          + "ub.v1.Topic\022/\n\013update_mask\030\002 \001(\0132\032.googl"
-          + "e.protobuf.FieldMask\"R\n\016PublishRequest\022\r"
-          + "\n\005topic\030\001 \001(\t\0221\n\010messages\030\002 \003(\0132\037.google"
-          + ".pubsub.v1.PubsubMessage\"&\n\017PublishRespo"
-          + "nse\022\023\n\013message_ids\030\001 \003(\t\"K\n\021ListTopicsRe"
-          + "quest\022\017\n\007project\030\001 \001(\t\022\021\n\tpage_size\030\002 \001("
-          + "\005\022\022\n\npage_token\030\003 \001(\t\"V\n\022ListTopicsRespo"
-          + "nse\022\'\n\006topics\030\001 \003(\0132\027.google.pubsub.v1.T"
-          + "opic\022\027\n\017next_page_token\030\002 \001(\t\"U\n\035ListTop"
-          + "icSubscriptionsRequest\022\r\n\005topic\030\001 \001(\t\022\021\n"
-          + "\tpage_size\030\002 \001(\005\022\022\n\npage_token\030\003 \001(\t\"P\n\036"
-          + "ListTopicSubscriptionsResponse\022\025\n\rsubscr"
-          + "iptions\030\001 \003(\t\022\027\n\017next_page_token\030\002 \001(\t\"Q"
-          + "\n\031ListTopicSnapshotsRequest\022\r\n\005topic\030\001 \001"
-          + "(\t\022\021\n\tpage_size\030\002 \001(\005\022\022\n\npage_token\030\003 \001("
-          + "\t\"H\n\032ListTopicSnapshotsResponse\022\021\n\tsnaps"
-          + "hots\030\001 \003(\t\022\027\n\017next_page_token\030\002 \001(\t\"#\n\022D"
-          + "eleteTopicRequest\022\r\n\005topic\030\001 \001(\t\"\345\003\n\014Sub"
-          + "scription\022\014\n\004name\030\001 \001(\t\022\r\n\005topic\030\002 \001(\t\0221"
-          + "\n\013push_config\030\004 \001(\0132\034.google.pubsub.v1.P"
-          + "ushConfig\022\034\n\024ack_deadline_seconds\030\005 \001(\005\022"
-          + "\035\n\025retain_acked_messages\030\007 \001(\010\022=\n\032messag"
-          + "e_retention_duration\030\010 \001(\0132\031.google.prot"
-          + "obuf.Duration\022:\n\006labels\030\t \003(\0132*.google.p"
-          + "ubsub.v1.Subscription.LabelsEntry\022\037\n\027ena"
-          + "ble_message_ordering\030\n \001(\010\022=\n\021expiration"
-          + "_policy\030\013 \001(\0132\".google.pubsub.v1.Expirat"
-          + "ionPolicy\022>\n\022dead_letter_policy\030\r \001(\0132\"."
-          + "google.pubsub.v1.DeadLetterPolicy\032-\n\013Lab"
-          + "elsEntry\022\013\n\003key\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\0028\001"
-          + "\"L\n\020DeadLetterPolicy\022\031\n\021dead_letter_topi"
-          + "c\030\001 \001(\t\022\035\n\025max_delivery_attempts\030\002 \001(\005\":"
-          + "\n\020ExpirationPolicy\022&\n\003ttl\030\001 \001(\0132\031.google"
-          + ".protobuf.Duration\"\255\002\n\nPushConfig\022\025\n\rpus"
-          + "h_endpoint\030\001 \001(\t\022@\n\nattributes\030\002 \003(\0132,.g"
-          + "oogle.pubsub.v1.PushConfig.AttributesEnt"
-          + "ry\022<\n\noidc_token\030\003 \001(\0132&.google.pubsub.v"
-          + "1.PushConfig.OidcTokenH\000\032<\n\tOidcToken\022\035\n"
-          + "\025service_account_email\030\001 \001(\t\022\020\n\010audience"
-          + "\030\002 \001(\t\0321\n\017AttributesEntry\022\013\n\003key\030\001 \001(\t\022\r"
-          + "\n\005value\030\002 \001(\t:\0028\001B\027\n\025authentication_meth"
-          + "od\"m\n\017ReceivedMessage\022\016\n\006ack_id\030\001 \001(\t\0220\n"
-          + "\007message\030\002 \001(\0132\037.google.pubsub.v1.Pubsub"
-          + "Message\022\030\n\020delivery_attempt\030\003 \001(\005\".\n\026Get"
-          + "SubscriptionRequest\022\024\n\014subscription\030\001 \001("
-          + "\t\"\202\001\n\031UpdateSubscriptionRequest\0224\n\014subsc"
-          + "ription\030\001 \001(\0132\036.google.pubsub.v1.Subscri"
-          + "ption\022/\n\013update_mask\030\002 \001(\0132\032.google.prot"
-          + "obuf.FieldMask\"R\n\030ListSubscriptionsReque"
-          + "st\022\017\n\007project\030\001 \001(\t\022\021\n\tpage_size\030\002 \001(\005\022\022"
-          + "\n\npage_token\030\003 \001(\t\"k\n\031ListSubscriptionsR"
-          + "esponse\0225\n\rsubscriptions\030\001 \003(\0132\036.google."
-          + "pubsub.v1.Subscription\022\027\n\017next_page_toke"
-          + "n\030\002 \001(\t\"1\n\031DeleteSubscriptionRequest\022\024\n\014"
-          + "subscription\030\001 \001(\t\"b\n\027ModifyPushConfigRe"
-          + "quest\022\024\n\014subscription\030\001 \001(\t\0221\n\013push_conf"
-          + "ig\030\002 \001(\0132\034.google.pubsub.v1.PushConfig\"U"
-          + "\n\013PullRequest\022\024\n\014subscription\030\001 \001(\t\022\032\n\022r"
-          + "eturn_immediately\030\002 \001(\010\022\024\n\014max_messages\030"
-          + "\003 \001(\005\"L\n\014PullResponse\022<\n\021received_messag"
-          + "es\030\001 \003(\0132!.google.pubsub.v1.ReceivedMess"
-          + "age\"_\n\030ModifyAckDeadlineRequest\022\024\n\014subsc"
-          + "ription\030\001 \001(\t\022\017\n\007ack_ids\030\004 \003(\t\022\034\n\024ack_de"
-          + "adline_seconds\030\003 \001(\005\";\n\022AcknowledgeReque"
-          + "st\022\024\n\014subscription\030\001 \001(\t\022\017\n\007ack_ids\030\002 \003("
-          + "\t\"\267\001\n\024StreamingPullRequest\022\024\n\014subscripti"
-          + "on\030\001 \001(\t\022\017\n\007ack_ids\030\002 \003(\t\022\037\n\027modify_dead"
-          + "line_seconds\030\003 \003(\005\022\037\n\027modify_deadline_ac"
-          + "k_ids\030\004 \003(\t\022#\n\033stream_ack_deadline_secon"
-          + "ds\030\005 \001(\005\022\021\n\tclient_id\030\006 \001(\t\"U\n\025Streaming"
-          + "PullResponse\022<\n\021received_messages\030\001 \003(\0132"
-          + "!.google.pubsub.v1.ReceivedMessage\"\257\001\n\025C"
-          + "reateSnapshotRequest\022\014\n\004name\030\001 \001(\t\022\024\n\014su"
-          + "bscription\030\002 \001(\t\022C\n\006labels\030\003 \003(\01323.googl"
-          + "e.pubsub.v1.CreateSnapshotRequest.Labels"
-          + "Entry\032-\n\013LabelsEntry\022\013\n\003key\030\001 \001(\t\022\r\n\005val"
-          + "ue\030\002 \001(\t:\0028\001\"v\n\025UpdateSnapshotRequest\022,\n"
-          + "\010snapshot\030\001 \001(\0132\032.google.pubsub.v1.Snaps"
-          + "hot\022/\n\013update_mask\030\002 \001(\0132\032.google.protob"
-          + "uf.FieldMask\"\277\001\n\010Snapshot\022\014\n\004name\030\001 \001(\t\022"
-          + "\r\n\005topic\030\002 \001(\t\022/\n\013expire_time\030\003 \001(\0132\032.go"
-          + "ogle.protobuf.Timestamp\0226\n\006labels\030\004 \003(\0132"
-          + "&.google.pubsub.v1.Snapshot.LabelsEntry\032"
-          + "-\n\013LabelsEntry\022\013\n\003key\030\001 \001(\t\022\r\n\005value\030\002 \001"
-          + "(\t:\0028\001\"&\n\022GetSnapshotRequest\022\020\n\010snapshot"
-          + "\030\001 \001(\t\"N\n\024ListSnapshotsRequest\022\017\n\007projec"
-          + "t\030\001 \001(\t\022\021\n\tpage_size\030\002 \001(\005\022\022\n\npage_token"
-          + "\030\003 \001(\t\"_\n\025ListSnapshotsResponse\022-\n\tsnaps"
-          + "hots\030\001 \003(\0132\032.google.pubsub.v1.Snapshot\022\027"
-          + "\n\017next_page_token\030\002 \001(\t\")\n\025DeleteSnapsho"
-          + "tRequest\022\020\n\010snapshot\030\001 \001(\t\"m\n\013SeekReques"
-          + "t\022\024\n\014subscription\030\001 \001(\t\022*\n\004time\030\002 \001(\0132\032."
-          + "google.protobuf.TimestampH\000\022\022\n\010snapshot\030"
-          + "\003 \001(\tH\000B\010\n\006target\"\016\n\014SeekResponse2\261\t\n\tPu"
-          + "blisher\022j\n\013CreateTopic\022\027.google.pubsub.v"
-          + "1.Topic\032\027.google.pubsub.v1.Topic\")\202\323\344\223\002#"
-          + "\032\036/v1/{name=projects/*/topics/*}:\001*\022}\n\013U"
-          + "pdateTopic\022$.google.pubsub.v1.UpdateTopi"
-          + "cRequest\032\027.google.pubsub.v1.Topic\"/\202\323\344\223\002"
-          + ")2$/v1/{topic.name=projects/*/topics/*}:"
-          + "\001*\022\202\001\n\007Publish\022 .google.pubsub.v1.Publis"
-          + "hRequest\032!.google.pubsub.v1.PublishRespo"
-          + "nse\"2\202\323\344\223\002,\"\'/v1/{topic=projects/*/topic"
-          + "s/*}:publish:\001*\022o\n\010GetTopic\022!.google.pub"
-          + "sub.v1.GetTopicRequest\032\027.google.pubsub.v"
-          + "1.Topic\"\'\202\323\344\223\002!\022\037/v1/{topic=projects/*/t"
-          + "opics/*}\022\200\001\n\nListTopics\022#.google.pubsub."
-          + "v1.ListTopicsRequest\032$.google.pubsub.v1."
-          + "ListTopicsResponse\"\'\202\323\344\223\002!\022\037/v1/{project"
-          + "=projects/*}/topics\022\262\001\n\026ListTopicSubscri"
-          + "ptions\022/.google.pubsub.v1.ListTopicSubsc"
-          + "riptionsRequest\0320.google.pubsub.v1.ListT"
-          + "opicSubscriptionsResponse\"5\202\323\344\223\002/\022-/v1/{"
-          + "topic=projects/*/topics/*}/subscriptions"
-          + "\022\242\001\n\022ListTopicSnapshots\022+.google.pubsub."
-          + "v1.ListTopicSnapshotsRequest\032,.google.pu"
-          + "bsub.v1.ListTopicSnapshotsResponse\"1\202\323\344\223"
-          + "\002+\022)/v1/{topic=projects/*/topics/*}/snap"
-          + "shots\022t\n\013DeleteTopic\022$.google.pubsub.v1."
-          + "DeleteTopicRequest\032\026.google.protobuf.Emp"
-          + "ty\"\'\202\323\344\223\002!*\037/v1/{topic=projects/*/topics"
-          + "/*}\032p\312A\025pubsub.googleapis.com\322AUhttps://"
-          + "www.googleapis.com/auth/cloud-platform,h"
-          + "ttps://www.googleapis.com/auth/pubsub2\353\022"
-          + "\n\nSubscriber\022\206\001\n\022CreateSubscription\022\036.go"
-          + "ogle.pubsub.v1.Subscription\032\036.google.pub"
-          + "sub.v1.Subscription\"0\202\323\344\223\002*\032%/v1/{name=p"
-          + "rojects/*/subscriptions/*}:\001*\022\222\001\n\017GetSub"
-          + "scription\022(.google.pubsub.v1.GetSubscrip"
-          + "tionRequest\032\036.google.pubsub.v1.Subscript"
-          + "ion\"5\202\323\344\223\002/\022-/v1/{subscription=projects/"
-          + "*/subscriptions/*}\022\240\001\n\022UpdateSubscriptio"
-          + "n\022+.google.pubsub.v1.UpdateSubscriptionR"
-          + "equest\032\036.google.pubsub.v1.Subscription\"="
-          + "\202\323\344\223\002722/v1/{subscription.name=projects/"
-          + "*/subscriptions/*}:\001*\022\234\001\n\021ListSubscripti"
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-          + "Request\032+.google.pubsub.v1.ListSubscript"
-          + "ionsResponse\".\202\323\344\223\002(\022&/v1/{project=proje"
-          + "cts/*}/subscriptions\022\220\001\n\022DeleteSubscript"
-          + "ion\022+.google.pubsub.v1.DeleteSubscriptio"
-          + "nRequest\032\026.google.protobuf.Empty\"5\202\323\344\223\002/"
-          + "*-/v1/{subscription=projects/*/subscript"
-          + "ions/*}\022\243\001\n\021ModifyAckDeadline\022*.google.p"
-          + "ubsub.v1.ModifyAckDeadlineRequest\032\026.goog"
-          + "le.protobuf.Empty\"J\202\323\344\223\002D\"?/v1/{subscrip"
-          + "tion=projects/*/subscriptions/*}:modifyA"
-          + "ckDeadline:\001*\022\221\001\n\013Acknowledge\022$.google.p"
-          + "ubsub.v1.AcknowledgeRequest\032\026.google.pro"
-          + "tobuf.Empty\"D\202\323\344\223\002>\"9/v1/{subscription=p"
-          + "rojects/*/subscriptions/*}:acknowledge:\001"
-          + "*\022\204\001\n\004Pull\022\035.google.pubsub.v1.PullReques"
-          + "t\032\036.google.pubsub.v1.PullResponse\"=\202\323\344\223\002"
-          + "7\"2/v1/{subscription=projects/*/subscrip"
-          + "tions/*}:pull:\001*\022f\n\rStreamingPull\022&.goog"
-          + "le.pubsub.v1.StreamingPullRequest\032\'.goog"
-          + "le.pubsub.v1.StreamingPullResponse\"\000(\0010\001"
-          + "\022\240\001\n\020ModifyPushConfig\022).google.pubsub.v1"
-          + ".ModifyPushConfigRequest\032\026.google.protob"
-          + "uf.Empty\"I\202\323\344\223\002C\">/v1/{subscription=proj"
-          + "ects/*/subscriptions/*}:modifyPushConfig"
-          + ":\001*\022~\n\013GetSnapshot\022$.google.pubsub.v1.Ge"
-          + "tSnapshotRequest\032\032.google.pubsub.v1.Snap"
-          + "shot\"-\202\323\344\223\002\'\022%/v1/{snapshot=projects/*/s"
-          + "napshots/*}\022\214\001\n\rListSnapshots\022&.google.p"
-          + "ubsub.v1.ListSnapshotsRequest\032\'.google.p"
-          + "ubsub.v1.ListSnapshotsResponse\"*\202\323\344\223\002$\022\""
-          + "/v1/{project=projects/*}/snapshots\022\203\001\n\016C"
-          + "reateSnapshot\022\'.google.pubsub.v1.CreateS"
-          + "napshotRequest\032\032.google.pubsub.v1.Snapsh"
-          + "ot\",\202\323\344\223\002&\032!/v1/{name=projects/*/snapsho"
-          + "ts/*}:\001*\022\214\001\n\016UpdateSnapshot\022\'.google.pub"
-          + "sub.v1.UpdateSnapshotRequest\032\032.google.pu"
-          + "bsub.v1.Snapshot\"5\202\323\344\223\002/2*/v1/{snapshot."
-          + "name=projects/*/snapshots/*}:\001*\022\200\001\n\016Dele"
-          + "teSnapshot\022\'.google.pubsub.v1.DeleteSnap"
-          + "shotRequest\032\026.google.protobuf.Empty\"-\202\323\344"
-          + "\223\002\'*%/v1/{snapshot=projects/*/snapshots/"
-          + "*}\022\204\001\n\004Seek\022\035.google.pubsub.v1.SeekReque"
-          + "st\032\036.google.pubsub.v1.SeekResponse\"=\202\323\344\223"
-          + "\0027\"2/v1/{subscription=projects/*/subscri"
-          + "ptions/*}:seek:\001*\032p\312A\025pubsub.googleapis."
-          + "com\322AUhttps://www.googleapis.com/auth/cl"
-          + "oud-platform,https://www.googleapis.com/"
-          + "auth/pubsubB\256\001\n\024com.google.pubsub.v1B\013Pu"
-          + "bsubProtoP\001Z6google.golang.org/genproto/"
-          + "googleapis/pubsub/v1;pubsub\370\001\001\252\002\026Google."
-          + "Cloud.PubSub.V1\312\002\026Google\\Cloud\\PubSub\\V1"
-          + "\352\002\031Google::Cloud::PubSub::V1b\006proto3"
+          + "pubsub.v1\032\027google/api/client.proto\032\037goog"
+          + "le/api/field_behavior.proto\032\031google/api/"
+          + "resource.proto\032\036google/protobuf/duration"
+          + ".proto\032\033google/protobuf/empty.proto\032 goo"
+          + "gle/protobuf/field_mask.proto\032\037google/pr"
+          + "otobuf/timestamp.proto\032\034google/api/annot"
+          + "ations.proto\";\n\024MessageStoragePolicy\022#\n\033"
+          + "allowed_persistence_regions\030\001 \003(\t\"\262\002\n\005To"
+          + "pic\022\021\n\004name\030\001 \001(\tB\003\340A\002\0223\n\006labels\030\002 \003(\0132#"
+          + ".google.pubsub.v1.Topic.LabelsEntry\022F\n\026m"
+          + "essage_storage_policy\030\003 \001(\0132&.google.pub"
+          + "sub.v1.MessageStoragePolicy\022\024\n\014kms_key_n"
+          + "ame\030\005 \001(\t\032-\n\013LabelsEntry\022\013\n\003key\030\001 \001(\t\022\r\n"
+          + "\005value\030\002 \001(\t:\0028\001:T\352AQ\n\033pubsub.googleapis"
+          + ".com/Topic\022!projects/{project}/topics/{t"
+          + "opic}\022\017_deleted-topic_\"\361\001\n\rPubsubMessage"
+          + "\022\014\n\004data\030\001 \001(\014\022C\n\nattributes\030\002 \003(\0132/.goo"
+          + "gle.pubsub.v1.PubsubMessage.AttributesEn"
+          + "try\022\022\n\nmessage_id\030\003 \001(\t\0220\n\014publish_time\030"
+          + "\004 \001(\0132\032.google.protobuf.Timestamp\022\024\n\014ord"
+          + "ering_key\030\005 \001(\t\0321\n\017AttributesEntry\022\013\n\003ke"
+          + "y\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\0028\001\"E\n\017GetTopicRe"
+          + "quest\0222\n\005topic\030\001 \001(\tB#\340A\002\372A\035\n\033pubsub.goo"
+          + "gleapis.com/Topic\"w\n\022UpdateTopicRequest\022"
+          + "+\n\005topic\030\001 \001(\0132\027.google.pubsub.v1.TopicB"
+          + "\003\340A\002\0224\n\013update_mask\030\002 \001(\0132\032.google.proto"
+          + "buf.FieldMaskB\003\340A\002\"|\n\016PublishRequest\0222\n\005"
+          + "topic\030\001 \001(\tB#\340A\002\372A\035\n\033pubsub.googleapis.c"
+          + "om/Topic\0226\n\010messages\030\002 \003(\0132\037.google.pubs"
+          + "ub.v1.PubsubMessageB\003\340A\002\"&\n\017PublishRespo"
+          + "nse\022\023\n\013message_ids\030\001 \003(\t\"\200\001\n\021ListTopicsR"
+          + "equest\022D\n\007project\030\001 \001(\tB3\340A\002\372A-\n+cloudre"
+          + "sourcemanager.googleapis.com/Project\022\021\n\t"
+          + "page_size\030\002 \001(\005\022\022\n\npage_token\030\003 \001(\t\"V\n\022L"
+          + "istTopicsResponse\022\'\n\006topics\030\001 \003(\0132\027.goog"
+          + "le.pubsub.v1.Topic\022\027\n\017next_page_token\030\002 "
+          + "\001(\t\"z\n\035ListTopicSubscriptionsRequest\0222\n\005"
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+          + "n\030\003 \001(\t\"y\n\036ListTopicSubscriptionsRespons"
+          + "e\022>\n\rsubscriptions\030\001 \003(\tB\'\372A$\n\"pubsub.go"
+          + "ogleapis.com/Subscription\022\027\n\017next_page_t"
+          + "oken\030\002 \001(\t\"Q\n\031ListTopicSnapshotsRequest\022"
+          + "\r\n\005topic\030\001 \001(\t\022\021\n\tpage_size\030\002 \001(\005\022\022\n\npag"
+          + "e_token\030\003 \001(\t\"H\n\032ListTopicSnapshotsRespo"
+          + "nse\022\021\n\tsnapshots\030\001 \003(\t\022\027\n\017next_page_toke"
+          + "n\030\002 \001(\t\"H\n\022DeleteTopicRequest\0222\n\005topic\030\001"
+          + " \001(\tB#\340A\002\372A\035\n\033pubsub.googleapis.com/Topi"
+          + "c\"\351\004\n\014Subscription\022\021\n\004name\030\001 \001(\tB\003\340A\002\0222\n"
+          + "\005topic\030\002 \001(\tB#\340A\002\372A\035\n\033pubsub.googleapis."
+          + "com/Topic\0221\n\013push_config\030\004 \001(\0132\034.google."
+          + "pubsub.v1.PushConfig\022\034\n\024ack_deadline_sec"
+          + "onds\030\005 \001(\005\022\035\n\025retain_acked_messages\030\007 \001("
+          + "\010\022=\n\032message_retention_duration\030\010 \001(\0132\031."
+          + "google.protobuf.Duration\022:\n\006labels\030\t \003(\013"
+          + "2*.google.pubsub.v1.Subscription.LabelsE"
+          + "ntry\022\037\n\027enable_message_ordering\030\n \001(\010\022=\n"
+          + "\021expiration_policy\030\013 \001(\0132\".google.pubsub"
+          + ".v1.ExpirationPolicy\022>\n\022dead_letter_poli"
+          + "cy\030\r \001(\0132\".google.pubsub.v1.DeadLetterPo"
+          + "licy\032-\n\013LabelsEntry\022\013\n\003key\030\001 \001(\t\022\r\n\005valu"
+          + "e\030\002 \001(\t:\0028\001:X\352AU\n\"pubsub.googleapis.com/"
+          + "Subscription\022/projects/{project}/subscri"
+          + "ptions/{subscription}\"L\n\020DeadLetterPolic"
+          + "y\022\031\n\021dead_letter_topic\030\001 \001(\t\022\035\n\025max_deli"
+          + "very_attempts\030\002 \001(\005\":\n\020ExpirationPolicy\022"
+          + "&\n\003ttl\030\001 \001(\0132\031.google.protobuf.Duration\""
+          + "\255\002\n\nPushConfig\022\025\n\rpush_endpoint\030\001 \001(\t\022@\n"
+          + "\nattributes\030\002 \003(\0132,.google.pubsub.v1.Pus"
+          + "hConfig.AttributesEntry\022<\n\noidc_token\030\003 "
+          + "\001(\0132&.google.pubsub.v1.PushConfig.OidcTo"
+          + "kenH\000\032<\n\tOidcToken\022\035\n\025service_account_em"
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+          + "sEntry\022\013\n\003key\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\0028\001B\027"
+          + "\n\025authentication_method\"m\n\017ReceivedMessa"
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+          + "ogle.pubsub.v1.PubsubMessage\022\030\n\020delivery"
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+          + "scriptionRequest\0229\n\014subscription\030\001 \001(\0132\036"
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+          + "pdate_mask\030\002 \001(\0132\032.google.protobuf.Field"
+          + "MaskB\003\340A\002\"\207\001\n\030ListSubscriptionsRequest\022D"
+          + "\n\007project\030\001 \001(\tB3\340A\002\372A-\n+cloudresourcema"
+          + "nager.googleapis.com/Project\022\021\n\tpage_siz"
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+          + "riptionsResponse\0225\n\rsubscriptions\030\001 \003(\0132"
+          + "\036.google.pubsub.v1.Subscription\022\027\n\017next_"
+          + "page_token\030\002 \001(\t\"]\n\031DeleteSubscriptionRe"
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+          + "sub.googleapis.com/Subscription\"\223\001\n\027Modi"
+          + "fyPushConfigRequest\022@\n\014subscription\030\001 \001("
+          + "\tB*\340A\002\372A$\n\"pubsub.googleapis.com/Subscri"
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+          + "ub.v1.PushConfigB\003\340A\002\"\206\001\n\013PullRequest\022@\n"
+          + "\014subscription\030\001 \001(\tB*\340A\002\372A$\n\"pubsub.goog"
+          + "leapis.com/Subscription\022\032\n\022return_immedi"
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+          + "\n\014PullResponse\022<\n\021received_messages\030\001 \003("
+          + "\0132!.google.pubsub.v1.ReceivedMessage\"\225\001\n"
+          + "\030ModifyAckDeadlineRequest\022@\n\014subscriptio"
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+          + "_deadline_seconds\030\003 \001(\005B\003\340A\002\"l\n\022Acknowle"
+          + "dgeRequest\022@\n\014subscription\030\001 \001(\tB*\340A\002\372A$"
+          + "\n\"pubsub.googleapis.com/Subscription\022\024\n\007"
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+          + "\n\021received_messages\030\001 \003(\0132!.google.pubsu"
+          + "b.v1.ReceivedMessage\"\203\002\n\025CreateSnapshotR"
+          + "equest\0224\n\004name\030\001 \001(\tB&\340A\002\372A \n\036pubsub.goo"
+          + "gleapis.com/Snapshot\022@\n\014subscription\030\002 \001"
+          + "(\tB*\340A\002\372A$\n\"pubsub.googleapis.com/Subscr"
+          + "iption\022C\n\006labels\030\003 \003(\01323.google.pubsub.v"
+          + "1.CreateSnapshotRequest.LabelsEntry\032-\n\013L"
+          + "abelsEntry\022\013\n\003key\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\002"
+          + "8\001\"\200\001\n\025UpdateSnapshotRequest\0221\n\010snapshot"
+          + "\030\001 \001(\0132\032.google.pubsub.v1.SnapshotB\003\340A\002\022"
+          + "4\n\013update_mask\030\002 \001(\0132\032.google.protobuf.F"
+          + "ieldMaskB\003\340A\002\"\257\002\n\010Snapshot\022\014\n\004name\030\001 \001(\t"
+          + "\022/\n\005topic\030\002 \001(\tB \372A\035\n\033pubsub.googleapis."
+          + "com/Topic\022/\n\013expire_time\030\003 \001(\0132\032.google."
+          + "protobuf.Timestamp\0226\n\006labels\030\004 \003(\0132&.goo"
+          + "gle.pubsub.v1.Snapshot.LabelsEntry\032-\n\013La"
+          + "belsEntry\022\013\n\003key\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\0028"
+          + "\001:L\352AI\n\036pubsub.googleapis.com/Snapshot\022\'"
+          + "projects/{project}/snapshots/{snapshot}\""
+          + "N\n\022GetSnapshotRequest\0228\n\010snapshot\030\001 \001(\tB"
+          + "&\340A\002\372A \n\036pubsub.googleapis.com/Snapshot\""
+          + "\203\001\n\024ListSnapshotsRequest\022D\n\007project\030\001 \001("
+          + "\tB3\340A\002\372A-\n+cloudresourcemanager.googleap"
+          + "is.com/Project\022\021\n\tpage_size\030\002 \001(\005\022\022\n\npag"
+          + "e_token\030\003 \001(\t\"_\n\025ListSnapshotsResponse\022-"
+          + "\n\tsnapshots\030\001 \003(\0132\032.google.pubsub.v1.Sna"
+          + "pshot\022\027\n\017next_page_token\030\002 \001(\t\"Q\n\025Delete"
+          + "SnapshotRequest\0228\n\010snapshot\030\001 \001(\tB&\340A\002\372A"
+          + " \n\036pubsub.googleapis.com/Snapshot\"\276\001\n\013Se"
+          + "ekRequest\022@\n\014subscription\030\001 \001(\tB*\340A\002\372A$\n"
+          + "\"pubsub.googleapis.com/Subscription\022*\n\004t"
+          + "ime\030\002 \001(\0132\032.google.protobuf.TimestampH\000\022"
+          + "7\n\010snapshot\030\003 \001(\tB#\372A \n\036pubsub.googleapi"
+          + "s.com/SnapshotH\000B\010\n\006target\"\016\n\014SeekRespon"
+          + "se2\353\t\n\tPublisher\022q\n\013CreateTopic\022\027.google"
+          + ".pubsub.v1.Topic\032\027.google.pubsub.v1.Topi"
+          + "c\"0\202\323\344\223\002#\032\036/v1/{name=projects/*/topics/*"
+          + "}:\001*\332A\004name\022}\n\013UpdateTopic\022$.google.pubs"
+          + "ub.v1.UpdateTopicRequest\032\027.google.pubsub"
+          + ".v1.Topic\"/\202\323\344\223\002)2$/v1/{topic.name=proje"
+          + "cts/*/topics/*}:\001*\022\223\001\n\007Publish\022 .google."
+          + "pubsub.v1.PublishRequest\032!.google.pubsub"
+          + ".v1.PublishResponse\"C\202\323\344\223\002,\"\'/v1/{topic="
+          + "projects/*/topics/*}:publish:\001*\332A\016topic,"
+          + "messages\022w\n\010GetTopic\022!.google.pubsub.v1."
+          + "GetTopicRequest\032\027.google.pubsub.v1.Topic"
+          + "\"/\202\323\344\223\002!\022\037/v1/{topic=projects/*/topics/*"
+          + "}\332A\005topic\022\212\001\n\nListTopics\022#.google.pubsub"
+          + ".v1.ListTopicsRequest\032$.google.pubsub.v1"
+          + ".ListTopicsResponse\"1\202\323\344\223\002!\022\037/v1/{projec"
+          + "t=projects/*}/topics\332A\007project\022\272\001\n\026ListT"
+          + "opicSubscriptions\022/.google.pubsub.v1.Lis"
+          + "tTopicSubscriptionsRequest\0320.google.pubs"
+          + "ub.v1.ListTopicSubscriptionsResponse\"=\202\323"
+          + "\344\223\002/\022-/v1/{topic=projects/*/topics/*}/su"
+          + "bscriptions\332A\005topic\022\242\001\n\022ListTopicSnapsho"
+          + "ts\022+.google.pubsub.v1.ListTopicSnapshots"
+          + "Request\032,.google.pubsub.v1.ListTopicSnap"
+          + "shotsResponse\"1\202\323\344\223\002+\022)/v1/{topic=projec"
+          + "ts/*/topics/*}/snapshots\022|\n\013DeleteTopic\022"
+          + "$.google.pubsub.v1.DeleteTopicRequest\032\026."
+          + "google.protobuf.Empty\"/\202\323\344\223\002!*\037/v1/{topi"
+          + "c=projects/*/topics/*}\332A\005topic\032p\312A\025pubsu"
+          + "b.googleapis.com\322AUhttps://www.googleapi"
+          + "s.com/auth/cloud-platform,https://www.go"
+          + "ogleapis.com/auth/pubsub2\367\024\n\nSubscriber\022"
+          + "\264\001\n\022CreateSubscription\022\036.google.pubsub.v"
+          + "1.Subscription\032\036.google.pubsub.v1.Subscr"
+          + "iption\"^\202\323\344\223\002*\032%/v1/{name=projects/*/sub"
+          + "scriptions/*}:\001*\332A+name,topic,push_confi"
+          + "g,ack_deadline_seconds\022\241\001\n\017GetSubscripti"
+          + "on\022(.google.pubsub.v1.GetSubscriptionReq"
+          + "uest\032\036.google.pubsub.v1.Subscription\"D\202\323"
+          + "\344\223\002/\022-/v1/{subscription=projects/*/subsc"
+          + "riptions/*}\332A\014subscription\022\240\001\n\022UpdateSub"
+          + "scription\022+.google.pubsub.v1.UpdateSubsc"
+          + "riptionRequest\032\036.google.pubsub.v1.Subscr"
+          + "iption\"=\202\323\344\223\002722/v1/{subscription.name=p"
+          + "rojects/*/subscriptions/*}:\001*\022\246\001\n\021ListSu"
+          + "bscriptions\022*.google.pubsub.v1.ListSubsc"
+          + "riptionsRequest\032+.google.pubsub.v1.ListS"
+          + "ubscriptionsResponse\"8\202\323\344\223\002(\022&/v1/{proje"
+          + "ct=projects/*}/subscriptions\332A\007project\022\237"
+          + "\001\n\022DeleteSubscription\022+.google.pubsub.v1"
+          + ".DeleteSubscriptionRequest\032\026.google.prot"
+          + "obuf.Empty\"D\202\323\344\223\002/*-/v1/{subscription=pr"
+          + "ojects/*/subscriptions/*}\332A\014subscription"
+          + "\022\317\001\n\021ModifyAckDeadline\022*.google.pubsub.v"
+          + "1.ModifyAckDeadlineRequest\032\026.google.prot"
+          + "obuf.Empty\"v\202\323\344\223\002D\"?/v1/{subscription=pr"
+          + "ojects/*/subscriptions/*}:modifyAckDeadl"
+          + "ine:\001*\332A)subscription,ack_ids,ack_deadli"
+          + "ne_seconds\022\250\001\n\013Acknowledge\022$.google.pubs"
+          + "ub.v1.AcknowledgeRequest\032\026.google.protob"
+          + "uf.Empty\"[\202\323\344\223\002>\"9/v1/{subscription=proj"
+          + "ects/*/subscriptions/*}:acknowledge:\001*\332A"
+          + "\024subscription,ack_ids\022\263\001\n\004Pull\022\035.google."
+          + "pubsub.v1.PullRequest\032\036.google.pubsub.v1"
+          + ".PullResponse\"l\202\323\344\223\0027\"2/v1/{subscription"
+          + "=projects/*/subscriptions/*}:pull:\001*\332A,s"
+          + "ubscription,return_immediately,max_messa"
+          + "ges\022f\n\rStreamingPull\022&.google.pubsub.v1."
+          + "StreamingPullRequest\032\'.google.pubsub.v1."
+          + "StreamingPullResponse\"\000(\0010\001\022\273\001\n\020ModifyPu"
+          + "shConfig\022).google.pubsub.v1.ModifyPushCo"
+          + "nfigRequest\032\026.google.protobuf.Empty\"d\202\323\344"
+          + "\223\002C\">/v1/{subscription=projects/*/subscr"
+          + "iptions/*}:modifyPushConfig:\001*\332A\030subscri"
+          + "ption,push_config\022~\n\013GetSnapshot\022$.googl"
+          + "e.pubsub.v1.GetSnapshotRequest\032\032.google."
+          + "pubsub.v1.Snapshot\"-\202\323\344\223\002\'\022%/v1/{snapsho"
+          + "t=projects/*/snapshots/*}\022\226\001\n\rListSnapsh"
+          + "ots\022&.google.pubsub.v1.ListSnapshotsRequ"
+          + "est\032\'.google.pubsub.v1.ListSnapshotsResp"
+          + "onse\"4\202\323\344\223\002$\022\"/v1/{project=projects/*}/s"
+          + "napshots\332A\007project\022\227\001\n\016CreateSnapshot\022\'."
+          + "google.pubsub.v1.CreateSnapshotRequest\032\032"
+          + ".google.pubsub.v1.Snapshot\"@\202\323\344\223\002&\032!/v1/"
+          + "{name=projects/*/snapshots/*}:\001*\332A\021name,"
+          + "subscription\022\214\001\n\016UpdateSnapshot\022\'.google"
+          + ".pubsub.v1.UpdateSnapshotRequest\032\032.googl"
+          + "e.pubsub.v1.Snapshot\"5\202\323\344\223\002/2*/v1/{snaps"
+          + "hot.name=projects/*/snapshots/*}:\001*\022\213\001\n\016"
+          + "DeleteSnapshot\022\'.google.pubsub.v1.Delete"
+          + "SnapshotRequest\032\026.google.protobuf.Empty\""
+          + "8\202\323\344\223\002\'*%/v1/{snapshot=projects/*/snapsh"
+          + "ots/*}\332A\010snapshot\022\204\001\n\004Seek\022\035.google.pubs"
+          + "ub.v1.SeekRequest\032\036.google.pubsub.v1.See"
+          + "kResponse\"=\202\323\344\223\0027\"2/v1/{subscription=pro"
+          + "jects/*/subscriptions/*}:seek:\001*\032p\312A\025pub"
+          + "sub.googleapis.com\322AUhttps://www.googlea"
+          + "pis.com/auth/cloud-platform,https://www."
+          + "googleapis.com/auth/pubsubB\256\001\n\024com.googl"
+          + "e.pubsub.v1B\013PubsubProtoP\001Z6google.golan"
+          + "g.org/genproto/googleapis/pubsub/v1;pubs"
+          + "ub\370\001\001\252\002\026Google.Cloud.PubSub.V1\312\002\026Google\\"
+          + "Cloud\\PubSub\\V1\352\002\031Google::Cloud::PubSub:"
+          + ":V1b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
             descriptorData,
             new com.google.protobuf.Descriptors.FileDescriptor[] {
-              com.google.api.AnnotationsProto.getDescriptor(),
               com.google.api.ClientProto.getDescriptor(),
+              com.google.api.FieldBehaviorProto.getDescriptor(),
+              com.google.api.ResourceProto.getDescriptor(),
               com.google.protobuf.DurationProto.getDescriptor(),
               com.google.protobuf.EmptyProto.getDescriptor(),
               com.google.protobuf.FieldMaskProto.getDescriptor(),
               com.google.protobuf.TimestampProto.getDescriptor(),
+              com.google.api.AnnotationsProto.getDescriptor(),
             });
     internal_static_google_pubsub_v1_MessageStoragePolicy_descriptor =
         getDescriptor().getMessageTypes().get(0);
@@ -835,16 +880,22 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
     com.google.protobuf.ExtensionRegistry registry =
         com.google.protobuf.ExtensionRegistry.newInstance();
     registry.add(com.google.api.ClientProto.defaultHost);
+    registry.add(com.google.api.FieldBehaviorProto.fieldBehavior);
     registry.add(com.google.api.AnnotationsProto.http);
+    registry.add(com.google.api.ClientProto.methodSignature);
     registry.add(com.google.api.ClientProto.oauthScopes);
+    registry.add(com.google.api.ResourceProto.resource);
+    registry.add(com.google.api.ResourceProto.resourceReference);
     com.google.protobuf.Descriptors.FileDescriptor.internalUpdateFileDescriptor(
         descriptor, registry);
-    com.google.api.AnnotationsProto.getDescriptor();
     com.google.api.ClientProto.getDescriptor();
+    com.google.api.FieldBehaviorProto.getDescriptor();
+    com.google.api.ResourceProto.getDescriptor();
     com.google.protobuf.DurationProto.getDescriptor();
     com.google.protobuf.EmptyProto.getDescriptor();
     com.google.protobuf.FieldMaskProto.getDescriptor();
     com.google.protobuf.TimestampProto.getDescriptor();
+    com.google.api.AnnotationsProto.getDescriptor();
   }
 
   // @@protoc_insertion_point(outer_class_scope)
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequest.java
index 5e5040d3b..2c6f5e56d 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequest.java
@@ -125,11 +125,13 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The subscription from which messages should be pulled.
+   * Required. The subscription from which messages should be pulled.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -148,11 +150,13 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The subscription from which messages should be pulled.
+   * Required. The subscription from which messages should be pulled.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -194,12 +198,12 @@ public boolean getReturnImmediately() {
    *
    *
    * <pre>
-   * The maximum number of messages to return for this request. Must be a
+   * Required. The maximum number of messages to return for this request. Must be a
    * positive integer. The Pub/Sub system may return fewer than the number
    * specified.
    * </pre>
    *
-   * <code>int32 max_messages = 3;</code>
+   * <code>int32 max_messages = 3 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The maxMessages.
    */
@@ -555,11 +559,13 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The subscription from which messages should be pulled.
+     * Required. The subscription from which messages should be pulled.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -578,11 +584,13 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The subscription from which messages should be pulled.
+     * Required. The subscription from which messages should be pulled.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -601,11 +609,13 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The subscription from which messages should be pulled.
+     * Required. The subscription from which messages should be pulled.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -623,11 +633,13 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The subscription from which messages should be pulled.
+     * Required. The subscription from which messages should be pulled.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -641,11 +653,13 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The subscription from which messages should be pulled.
+     * Required. The subscription from which messages should be pulled.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
@@ -726,12 +740,12 @@ public Builder clearReturnImmediately() {
      *
      *
      * <pre>
-     * The maximum number of messages to return for this request. Must be a
+     * Required. The maximum number of messages to return for this request. Must be a
      * positive integer. The Pub/Sub system may return fewer than the number
      * specified.
      * </pre>
      *
-     * <code>int32 max_messages = 3;</code>
+     * <code>int32 max_messages = 3 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The maxMessages.
      */
@@ -742,12 +756,12 @@ public int getMaxMessages() {
      *
      *
      * <pre>
-     * The maximum number of messages to return for this request. Must be a
+     * Required. The maximum number of messages to return for this request. Must be a
      * positive integer. The Pub/Sub system may return fewer than the number
      * specified.
      * </pre>
      *
-     * <code>int32 max_messages = 3;</code>
+     * <code>int32 max_messages = 3 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The maxMessages to set.
      * @return This builder for chaining.
@@ -762,12 +776,12 @@ public Builder setMaxMessages(int value) {
      *
      *
      * <pre>
-     * The maximum number of messages to return for this request. Must be a
+     * Required. The maximum number of messages to return for this request. Must be a
      * positive integer. The Pub/Sub system may return fewer than the number
      * specified.
      * </pre>
      *
-     * <code>int32 max_messages = 3;</code>
+     * <code>int32 max_messages = 3 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return This builder for chaining.
      */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequestOrBuilder.java
index 560e86987..a908386fb 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/PullRequestOrBuilder.java
@@ -27,11 +27,13 @@ public interface PullRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription from which messages should be pulled.
+   * Required. The subscription from which messages should be pulled.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -40,11 +42,13 @@ public interface PullRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription from which messages should be pulled.
+   * Required. The subscription from which messages should be pulled.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -70,12 +74,12 @@ public interface PullRequestOrBuilder
    *
    *
    * <pre>
-   * The maximum number of messages to return for this request. Must be a
+   * Required. The maximum number of messages to return for this request. Must be a
    * positive integer. The Pub/Sub system may return fewer than the number
    * specified.
    * </pre>
    *
-   * <code>int32 max_messages = 3;</code>
+   * <code>int32 max_messages = 3 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The maxMessages.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequest.java
index c4b9d62d3..7b5b68eeb 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequest.java
@@ -184,10 +184,12 @@ public TargetCase getTargetCase() {
    *
    *
    * <pre>
-   * The subscription to affect.
+   * Required. The subscription to affect.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -206,10 +208,12 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The subscription to affect.
+   * Required. The subscription to affect.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -313,7 +317,7 @@ public com.google.protobuf.TimestampOrBuilder getTimeOrBuilder() {
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 3;</code>
+   * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The snapshot.
    */
@@ -342,7 +346,7 @@ public java.lang.String getSnapshot() {
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 3;</code>
+   * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The bytes for snapshot.
    */
@@ -763,10 +767,12 @@ public Builder clearTarget() {
      *
      *
      * <pre>
-     * The subscription to affect.
+     * Required. The subscription to affect.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -785,10 +791,12 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The subscription to affect.
+     * Required. The subscription to affect.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -807,10 +815,12 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The subscription to affect.
+     * Required. The subscription to affect.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -828,10 +838,12 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The subscription to affect.
+     * Required. The subscription to affect.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -845,10 +857,12 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The subscription to affect.
+     * Required. The subscription to affect.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
@@ -1164,7 +1178,7 @@ public com.google.protobuf.TimestampOrBuilder getTimeOrBuilder() {
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 3;</code>
+     * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return The snapshot.
      */
@@ -1193,7 +1207,7 @@ public java.lang.String getSnapshot() {
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 3;</code>
+     * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return The bytes for snapshot.
      */
@@ -1222,7 +1236,7 @@ public com.google.protobuf.ByteString getSnapshotBytes() {
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 3;</code>
+     * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param value The snapshot to set.
      * @return This builder for chaining.
@@ -1245,7 +1259,7 @@ public Builder setSnapshot(java.lang.String value) {
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 3;</code>
+     * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return This builder for chaining.
      */
@@ -1266,7 +1280,7 @@ public Builder clearSnapshot() {
      * Format is `projects/{project}/snapshots/{snap}`.
      * </pre>
      *
-     * <code>string snapshot = 3;</code>
+     * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param value The bytes for snapshot to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequestOrBuilder.java
index 3d23318fb..bff70a803 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SeekRequestOrBuilder.java
@@ -27,10 +27,12 @@ public interface SeekRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription to affect.
+   * Required. The subscription to affect.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -39,10 +41,12 @@ public interface SeekRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription to affect.
+   * Required. The subscription to affect.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -122,7 +126,7 @@ public interface SeekRequestOrBuilder
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 3;</code>
+   * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The snapshot.
    */
@@ -136,7 +140,7 @@ public interface SeekRequestOrBuilder
    * Format is `projects/{project}/snapshots/{snap}`.
    * </pre>
    *
-   * <code>string snapshot = 3;</code>
+   * <code>string snapshot = 3 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The bytes for snapshot.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Snapshot.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Snapshot.java
index b87a227be..bebe34404 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Snapshot.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Snapshot.java
@@ -218,7 +218,7 @@ public com.google.protobuf.ByteString getNameBytes() {
    * The name of the topic from which this snapshot is retaining messages.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The topic.
    */
@@ -240,7 +240,7 @@ public java.lang.String getTopic() {
    * The name of the topic from which this snapshot is retaining messages.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The bytes for topic.
    */
@@ -940,7 +940,7 @@ public Builder setNameBytes(com.google.protobuf.ByteString value) {
      * The name of the topic from which this snapshot is retaining messages.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return The topic.
      */
@@ -962,7 +962,7 @@ public java.lang.String getTopic() {
      * The name of the topic from which this snapshot is retaining messages.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return The bytes for topic.
      */
@@ -984,7 +984,7 @@ public com.google.protobuf.ByteString getTopicBytes() {
      * The name of the topic from which this snapshot is retaining messages.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param value The topic to set.
      * @return This builder for chaining.
@@ -1005,7 +1005,7 @@ public Builder setTopic(java.lang.String value) {
      * The name of the topic from which this snapshot is retaining messages.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
      *
      * @return This builder for chaining.
      */
@@ -1022,7 +1022,7 @@ public Builder clearTopic() {
      * The name of the topic from which this snapshot is retaining messages.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
      *
      * @param value The bytes for topic to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SnapshotOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SnapshotOrBuilder.java
index be8ea184d..9ef1ef752 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SnapshotOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SnapshotOrBuilder.java
@@ -55,7 +55,7 @@ public interface SnapshotOrBuilder
    * The name of the topic from which this snapshot is retaining messages.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The topic.
    */
@@ -67,7 +67,7 @@ public interface SnapshotOrBuilder
    * The name of the topic from which this snapshot is retaining messages.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>string topic = 2 [(.google.api.resource_reference) = { ... }</code>
    *
    * @return The bytes for topic.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequest.java
index 480253f70..cf748b70c 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequest.java
@@ -188,13 +188,15 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The subscription for which to initialize the new stream. This must be
+   * Required. The subscription for which to initialize the new stream. This must be
    * provided in the first request on the stream, and must not be set in
    * subsequent requests from client to server.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -213,13 +215,15 @@ public java.lang.String getSubscription() {
    *
    *
    * <pre>
-   * The subscription for which to initialize the new stream. This must be
+   * Required. The subscription for which to initialize the new stream. This must be
    * provided in the first request on the stream, and must not be set in
    * subsequent requests from client to server.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -473,13 +477,13 @@ public com.google.protobuf.ByteString getModifyDeadlineAckIdsBytes(int index) {
    *
    *
    * <pre>
-   * The ack deadline to use for the stream. This must be provided in the
+   * Required. The ack deadline to use for the stream. This must be provided in the
    * first request on the stream, but it can also be updated on subsequent
    * requests from client to server. The minimum deadline you can specify is 10
    * seconds. The maximum deadline you can specify is 600 seconds (10 minutes).
    * </pre>
    *
-   * <code>int32 stream_ack_deadline_seconds = 5;</code>
+   * <code>int32 stream_ack_deadline_seconds = 5 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The streamAckDeadlineSeconds.
    */
@@ -1012,13 +1016,15 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The subscription for which to initialize the new stream. This must be
+     * Required. The subscription for which to initialize the new stream. This must be
      * provided in the first request on the stream, and must not be set in
      * subsequent requests from client to server.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The subscription.
      */
@@ -1037,13 +1043,15 @@ public java.lang.String getSubscription() {
      *
      *
      * <pre>
-     * The subscription for which to initialize the new stream. This must be
+     * Required. The subscription for which to initialize the new stream. This must be
      * provided in the first request on the stream, and must not be set in
      * subsequent requests from client to server.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for subscription.
      */
@@ -1062,13 +1070,15 @@ public com.google.protobuf.ByteString getSubscriptionBytes() {
      *
      *
      * <pre>
-     * The subscription for which to initialize the new stream. This must be
+     * Required. The subscription for which to initialize the new stream. This must be
      * provided in the first request on the stream, and must not be set in
      * subsequent requests from client to server.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The subscription to set.
      * @return This builder for chaining.
@@ -1086,13 +1096,15 @@ public Builder setSubscription(java.lang.String value) {
      *
      *
      * <pre>
-     * The subscription for which to initialize the new stream. This must be
+     * Required. The subscription for which to initialize the new stream. This must be
      * provided in the first request on the stream, and must not be set in
      * subsequent requests from client to server.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -1106,13 +1118,15 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The subscription for which to initialize the new stream. This must be
+     * Required. The subscription for which to initialize the new stream. This must be
      * provided in the first request on the stream, and must not be set in
      * subsequent requests from client to server.
      * Format is `projects/{project}/subscriptions/{sub}`.
      * </pre>
      *
-     * <code>string subscription = 1;</code>
+     * <code>
+     * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for subscription to set.
      * @return This builder for chaining.
@@ -1738,13 +1752,13 @@ public Builder addModifyDeadlineAckIdsBytes(com.google.protobuf.ByteString value
      *
      *
      * <pre>
-     * The ack deadline to use for the stream. This must be provided in the
+     * Required. The ack deadline to use for the stream. This must be provided in the
      * first request on the stream, but it can also be updated on subsequent
      * requests from client to server. The minimum deadline you can specify is 10
      * seconds. The maximum deadline you can specify is 600 seconds (10 minutes).
      * </pre>
      *
-     * <code>int32 stream_ack_deadline_seconds = 5;</code>
+     * <code>int32 stream_ack_deadline_seconds = 5 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The streamAckDeadlineSeconds.
      */
@@ -1755,13 +1769,13 @@ public int getStreamAckDeadlineSeconds() {
      *
      *
      * <pre>
-     * The ack deadline to use for the stream. This must be provided in the
+     * Required. The ack deadline to use for the stream. This must be provided in the
      * first request on the stream, but it can also be updated on subsequent
      * requests from client to server. The minimum deadline you can specify is 10
      * seconds. The maximum deadline you can specify is 600 seconds (10 minutes).
      * </pre>
      *
-     * <code>int32 stream_ack_deadline_seconds = 5;</code>
+     * <code>int32 stream_ack_deadline_seconds = 5 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The streamAckDeadlineSeconds to set.
      * @return This builder for chaining.
@@ -1776,13 +1790,13 @@ public Builder setStreamAckDeadlineSeconds(int value) {
      *
      *
      * <pre>
-     * The ack deadline to use for the stream. This must be provided in the
+     * Required. The ack deadline to use for the stream. This must be provided in the
      * first request on the stream, but it can also be updated on subsequent
      * requests from client to server. The minimum deadline you can specify is 10
      * seconds. The maximum deadline you can specify is 600 seconds (10 minutes).
      * </pre>
      *
-     * <code>int32 stream_ack_deadline_seconds = 5;</code>
+     * <code>int32 stream_ack_deadline_seconds = 5 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return This builder for chaining.
      */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequestOrBuilder.java
index e9315a90f..daed9c34d 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/StreamingPullRequestOrBuilder.java
@@ -27,13 +27,15 @@ public interface StreamingPullRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription for which to initialize the new stream. This must be
+   * Required. The subscription for which to initialize the new stream. This must be
    * provided in the first request on the stream, and must not be set in
    * subsequent requests from client to server.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The subscription.
    */
@@ -42,13 +44,15 @@ public interface StreamingPullRequestOrBuilder
    *
    *
    * <pre>
-   * The subscription for which to initialize the new stream. This must be
+   * Required. The subscription for which to initialize the new stream. This must be
    * provided in the first request on the stream, and must not be set in
    * subsequent requests from client to server.
    * Format is `projects/{project}/subscriptions/{sub}`.
    * </pre>
    *
-   * <code>string subscription = 1;</code>
+   * <code>
+   * string subscription = 1 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for subscription.
    */
@@ -260,13 +264,13 @@ public interface StreamingPullRequestOrBuilder
    *
    *
    * <pre>
-   * The ack deadline to use for the stream. This must be provided in the
+   * Required. The ack deadline to use for the stream. This must be provided in the
    * first request on the stream, but it can also be updated on subsequent
    * requests from client to server. The minimum deadline you can specify is 10
    * seconds. The maximum deadline you can specify is 600 seconds (10 minutes).
    * </pre>
    *
-   * <code>int32 stream_ack_deadline_seconds = 5;</code>
+   * <code>int32 stream_ack_deadline_seconds = 5 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The streamAckDeadlineSeconds.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Subscription.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Subscription.java
index 468e9b2cc..af7af8ecd 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Subscription.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Subscription.java
@@ -227,7 +227,7 @@ protected com.google.protobuf.MapField internalGetMapField(int number) {
    *
    *
    * <pre>
-   * The name of the subscription. It must have the format
+   * Required. The name of the subscription. It must have the format
    * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
    * start with a letter, and contain only letters (`[A-Za-z]`), numbers
    * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -235,7 +235,7 @@ protected com.google.protobuf.MapField internalGetMapField(int number) {
    * in length, and it must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The name.
    */
@@ -254,7 +254,7 @@ public java.lang.String getName() {
    *
    *
    * <pre>
-   * The name of the subscription. It must have the format
+   * Required. The name of the subscription. It must have the format
    * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
    * start with a letter, and contain only letters (`[A-Za-z]`), numbers
    * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -262,7 +262,7 @@ public java.lang.String getName() {
    * in length, and it must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The bytes for name.
    */
@@ -284,13 +284,15 @@ public com.google.protobuf.ByteString getNameBytes() {
    *
    *
    * <pre>
-   * The name of the topic from which this subscription is receiving messages.
+   * Required. The name of the topic from which this subscription is receiving messages.
    * Format is `projects/{project}/topics/{topic}`.
    * The value of this field will be `_deleted-topic_` if the topic has been
    * deleted.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>
+   * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -309,13 +311,15 @@ public java.lang.String getTopic() {
    *
    *
    * <pre>
-   * The name of the topic from which this subscription is receiving messages.
+   * Required. The name of the topic from which this subscription is receiving messages.
    * Format is `projects/{project}/topics/{topic}`.
    * The value of this field will be `_deleted-topic_` if the topic has been
    * deleted.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>
+   * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
@@ -1285,7 +1289,7 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the subscription. It must have the format
+     * Required. The name of the subscription. It must have the format
      * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
      * start with a letter, and contain only letters (`[A-Za-z]`), numbers
      * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -1293,7 +1297,7 @@ public Builder mergeFrom(
      * in length, and it must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The name.
      */
@@ -1312,7 +1316,7 @@ public java.lang.String getName() {
      *
      *
      * <pre>
-     * The name of the subscription. It must have the format
+     * Required. The name of the subscription. It must have the format
      * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
      * start with a letter, and contain only letters (`[A-Za-z]`), numbers
      * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -1320,7 +1324,7 @@ public java.lang.String getName() {
      * in length, and it must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The bytes for name.
      */
@@ -1339,7 +1343,7 @@ public com.google.protobuf.ByteString getNameBytes() {
      *
      *
      * <pre>
-     * The name of the subscription. It must have the format
+     * Required. The name of the subscription. It must have the format
      * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
      * start with a letter, and contain only letters (`[A-Za-z]`), numbers
      * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -1347,7 +1351,7 @@ public com.google.protobuf.ByteString getNameBytes() {
      * in length, and it must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The name to set.
      * @return This builder for chaining.
@@ -1365,7 +1369,7 @@ public Builder setName(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the subscription. It must have the format
+     * Required. The name of the subscription. It must have the format
      * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
      * start with a letter, and contain only letters (`[A-Za-z]`), numbers
      * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -1373,7 +1377,7 @@ public Builder setName(java.lang.String value) {
      * in length, and it must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return This builder for chaining.
      */
@@ -1387,7 +1391,7 @@ public Builder clearName() {
      *
      *
      * <pre>
-     * The name of the subscription. It must have the format
+     * Required. The name of the subscription. It must have the format
      * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
      * start with a letter, and contain only letters (`[A-Za-z]`), numbers
      * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -1395,7 +1399,7 @@ public Builder clearName() {
      * in length, and it must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The bytes for name to set.
      * @return This builder for chaining.
@@ -1416,13 +1420,15 @@ public Builder setNameBytes(com.google.protobuf.ByteString value) {
      *
      *
      * <pre>
-     * The name of the topic from which this subscription is receiving messages.
+     * Required. The name of the topic from which this subscription is receiving messages.
      * Format is `projects/{project}/topics/{topic}`.
      * The value of this field will be `_deleted-topic_` if the topic has been
      * deleted.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>
+     * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The topic.
      */
@@ -1441,13 +1447,15 @@ public java.lang.String getTopic() {
      *
      *
      * <pre>
-     * The name of the topic from which this subscription is receiving messages.
+     * Required. The name of the topic from which this subscription is receiving messages.
      * Format is `projects/{project}/topics/{topic}`.
      * The value of this field will be `_deleted-topic_` if the topic has been
      * deleted.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>
+     * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return The bytes for topic.
      */
@@ -1466,13 +1474,15 @@ public com.google.protobuf.ByteString getTopicBytes() {
      *
      *
      * <pre>
-     * The name of the topic from which this subscription is receiving messages.
+     * Required. The name of the topic from which this subscription is receiving messages.
      * Format is `projects/{project}/topics/{topic}`.
      * The value of this field will be `_deleted-topic_` if the topic has been
      * deleted.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>
+     * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The topic to set.
      * @return This builder for chaining.
@@ -1490,13 +1500,15 @@ public Builder setTopic(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the topic from which this subscription is receiving messages.
+     * Required. The name of the topic from which this subscription is receiving messages.
      * Format is `projects/{project}/topics/{topic}`.
      * The value of this field will be `_deleted-topic_` if the topic has been
      * deleted.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>
+     * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @return This builder for chaining.
      */
@@ -1510,13 +1522,15 @@ public Builder clearTopic() {
      *
      *
      * <pre>
-     * The name of the topic from which this subscription is receiving messages.
+     * Required. The name of the topic from which this subscription is receiving messages.
      * Format is `projects/{project}/topics/{topic}`.
      * The value of this field will be `_deleted-topic_` if the topic has been
      * deleted.
      * </pre>
      *
-     * <code>string topic = 2;</code>
+     * <code>
+     * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+     * </code>
      *
      * @param value The bytes for topic to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SubscriptionOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SubscriptionOrBuilder.java
index 7b2e4648a..840cd7f6a 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SubscriptionOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/SubscriptionOrBuilder.java
@@ -27,7 +27,7 @@ public interface SubscriptionOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription. It must have the format
+   * Required. The name of the subscription. It must have the format
    * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
    * start with a letter, and contain only letters (`[A-Za-z]`), numbers
    * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -35,7 +35,7 @@ public interface SubscriptionOrBuilder
    * in length, and it must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The name.
    */
@@ -44,7 +44,7 @@ public interface SubscriptionOrBuilder
    *
    *
    * <pre>
-   * The name of the subscription. It must have the format
+   * Required. The name of the subscription. It must have the format
    * `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
    * start with a letter, and contain only letters (`[A-Za-z]`), numbers
    * (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
@@ -52,7 +52,7 @@ public interface SubscriptionOrBuilder
    * in length, and it must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The bytes for name.
    */
@@ -62,13 +62,15 @@ public interface SubscriptionOrBuilder
    *
    *
    * <pre>
-   * The name of the topic from which this subscription is receiving messages.
+   * Required. The name of the topic from which this subscription is receiving messages.
    * Format is `projects/{project}/topics/{topic}`.
    * The value of this field will be `_deleted-topic_` if the topic has been
    * deleted.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>
+   * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The topic.
    */
@@ -77,13 +79,15 @@ public interface SubscriptionOrBuilder
    *
    *
    * <pre>
-   * The name of the topic from which this subscription is receiving messages.
+   * Required. The name of the topic from which this subscription is receiving messages.
    * Format is `projects/{project}/topics/{topic}`.
    * The value of this field will be `_deleted-topic_` if the topic has been
    * deleted.
    * </pre>
    *
-   * <code>string topic = 2;</code>
+   * <code>
+   * string topic = 2 [(.google.api.field_behavior) = REQUIRED, (.google.api.resource_reference) = { ... }
+   * </code>
    *
    * @return The bytes for topic.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Topic.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Topic.java
index 3d29b4fa3..e062abc0e 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Topic.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/Topic.java
@@ -164,7 +164,7 @@ protected com.google.protobuf.MapField internalGetMapField(int number) {
    *
    *
    * <pre>
-   * The name of the topic. It must have the format
+   * Required. The name of the topic. It must have the format
    * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
    * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
    * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -172,7 +172,7 @@ protected com.google.protobuf.MapField internalGetMapField(int number) {
    * must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The name.
    */
@@ -191,7 +191,7 @@ public java.lang.String getName() {
    *
    *
    * <pre>
-   * The name of the topic. It must have the format
+   * Required. The name of the topic. It must have the format
    * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
    * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
    * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -199,7 +199,7 @@ public java.lang.String getName() {
    * must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The bytes for name.
    */
@@ -818,7 +818,7 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the topic. It must have the format
+     * Required. The name of the topic. It must have the format
      * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
      * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
      * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -826,7 +826,7 @@ public Builder mergeFrom(
      * must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The name.
      */
@@ -845,7 +845,7 @@ public java.lang.String getName() {
      *
      *
      * <pre>
-     * The name of the topic. It must have the format
+     * Required. The name of the topic. It must have the format
      * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
      * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
      * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -853,7 +853,7 @@ public java.lang.String getName() {
      * must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The bytes for name.
      */
@@ -872,7 +872,7 @@ public com.google.protobuf.ByteString getNameBytes() {
      *
      *
      * <pre>
-     * The name of the topic. It must have the format
+     * Required. The name of the topic. It must have the format
      * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
      * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
      * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -880,7 +880,7 @@ public com.google.protobuf.ByteString getNameBytes() {
      * must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The name to set.
      * @return This builder for chaining.
@@ -898,7 +898,7 @@ public Builder setName(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the topic. It must have the format
+     * Required. The name of the topic. It must have the format
      * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
      * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
      * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -906,7 +906,7 @@ public Builder setName(java.lang.String value) {
      * must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return This builder for chaining.
      */
@@ -920,7 +920,7 @@ public Builder clearName() {
      *
      *
      * <pre>
-     * The name of the topic. It must have the format
+     * Required. The name of the topic. It must have the format
      * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
      * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
      * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -928,7 +928,7 @@ public Builder clearName() {
      * must not start with `"goog"`.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @param value The bytes for name to set.
      * @return This builder for chaining.
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/TopicOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/TopicOrBuilder.java
index a2d605d8c..1e1338b11 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/TopicOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/TopicOrBuilder.java
@@ -27,7 +27,7 @@ public interface TopicOrBuilder
    *
    *
    * <pre>
-   * The name of the topic. It must have the format
+   * Required. The name of the topic. It must have the format
    * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
    * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
    * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -35,7 +35,7 @@ public interface TopicOrBuilder
    * must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The name.
    */
@@ -44,7 +44,7 @@ public interface TopicOrBuilder
    *
    *
    * <pre>
-   * The name of the topic. It must have the format
+   * Required. The name of the topic. It must have the format
    * `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
    * and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
    * underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
@@ -52,7 +52,7 @@ public interface TopicOrBuilder
    * must not start with `"goog"`.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The bytes for name.
    */
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequest.java
index 79176925b..b22075d56 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequest.java
@@ -138,10 +138,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The updated snapshot object.
+   * Required. The updated snapshot object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+   * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return Whether the snapshot field is set.
    */
@@ -152,10 +152,10 @@ public boolean hasSnapshot() {
    *
    *
    * <pre>
-   * The updated snapshot object.
+   * Required. The updated snapshot object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+   * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The snapshot.
    */
@@ -166,10 +166,10 @@ public com.google.pubsub.v1.Snapshot getSnapshot() {
    *
    *
    * <pre>
-   * The updated snapshot object.
+   * Required. The updated snapshot object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+   * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    */
   public com.google.pubsub.v1.SnapshotOrBuilder getSnapshotOrBuilder() {
     return getSnapshot();
@@ -181,11 +181,12 @@ public com.google.pubsub.v1.SnapshotOrBuilder getSnapshotOrBuilder() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided snapshot to update.
+   * Required. Indicates which fields in the provided snapshot to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the updateMask field is set.
    */
@@ -196,11 +197,12 @@ public boolean hasUpdateMask() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided snapshot to update.
+   * Required. Indicates which fields in the provided snapshot to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The updateMask.
    */
@@ -211,11 +213,12 @@ public com.google.protobuf.FieldMask getUpdateMask() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided snapshot to update.
+   * Required. Indicates which fields in the provided snapshot to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
     return getUpdateMask();
@@ -587,10 +590,11 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return Whether the snapshot field is set.
      */
@@ -601,10 +605,11 @@ public boolean hasSnapshot() {
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return The snapshot.
      */
@@ -619,10 +624,11 @@ public com.google.pubsub.v1.Snapshot getSnapshot() {
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setSnapshot(com.google.pubsub.v1.Snapshot value) {
       if (snapshotBuilder_ == null) {
@@ -641,10 +647,11 @@ public Builder setSnapshot(com.google.pubsub.v1.Snapshot value) {
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setSnapshot(com.google.pubsub.v1.Snapshot.Builder builderForValue) {
       if (snapshotBuilder_ == null) {
@@ -660,10 +667,11 @@ public Builder setSnapshot(com.google.pubsub.v1.Snapshot.Builder builderForValue
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder mergeSnapshot(com.google.pubsub.v1.Snapshot value) {
       if (snapshotBuilder_ == null) {
@@ -684,10 +692,11 @@ public Builder mergeSnapshot(com.google.pubsub.v1.Snapshot value) {
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder clearSnapshot() {
       if (snapshotBuilder_ == null) {
@@ -704,10 +713,11 @@ public Builder clearSnapshot() {
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.Snapshot.Builder getSnapshotBuilder() {
 
@@ -718,10 +728,11 @@ public com.google.pubsub.v1.Snapshot.Builder getSnapshotBuilder() {
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.SnapshotOrBuilder getSnapshotOrBuilder() {
       if (snapshotBuilder_ != null) {
@@ -734,10 +745,11 @@ public com.google.pubsub.v1.SnapshotOrBuilder getSnapshotOrBuilder() {
      *
      *
      * <pre>
-     * The updated snapshot object.
+     * Required. The updated snapshot object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+     * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.pubsub.v1.Snapshot,
@@ -766,11 +778,12 @@ public com.google.pubsub.v1.SnapshotOrBuilder getSnapshotOrBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return Whether the updateMask field is set.
      */
@@ -781,11 +794,12 @@ public boolean hasUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return The updateMask.
      */
@@ -802,11 +816,12 @@ public com.google.protobuf.FieldMask getUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setUpdateMask(com.google.protobuf.FieldMask value) {
       if (updateMaskBuilder_ == null) {
@@ -825,11 +840,12 @@ public Builder setUpdateMask(com.google.protobuf.FieldMask value) {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForValue) {
       if (updateMaskBuilder_ == null) {
@@ -845,11 +861,12 @@ public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForVal
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder mergeUpdateMask(com.google.protobuf.FieldMask value) {
       if (updateMaskBuilder_ == null) {
@@ -870,11 +887,12 @@ public Builder mergeUpdateMask(com.google.protobuf.FieldMask value) {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder clearUpdateMask() {
       if (updateMaskBuilder_ == null) {
@@ -891,11 +909,12 @@ public Builder clearUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.protobuf.FieldMask.Builder getUpdateMaskBuilder() {
 
@@ -906,11 +925,12 @@ public com.google.protobuf.FieldMask.Builder getUpdateMaskBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
       if (updateMaskBuilder_ != null) {
@@ -925,11 +945,12 @@ public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided snapshot to update.
+     * Required. Indicates which fields in the provided snapshot to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.protobuf.FieldMask,
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequestOrBuilder.java
index 927d77a34..2acbd1120 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSnapshotRequestOrBuilder.java
@@ -27,10 +27,10 @@ public interface UpdateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The updated snapshot object.
+   * Required. The updated snapshot object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+   * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return Whether the snapshot field is set.
    */
@@ -39,10 +39,10 @@ public interface UpdateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The updated snapshot object.
+   * Required. The updated snapshot object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+   * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The snapshot.
    */
@@ -51,10 +51,10 @@ public interface UpdateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * The updated snapshot object.
+   * Required. The updated snapshot object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Snapshot snapshot = 1;</code>
+   * <code>.google.pubsub.v1.Snapshot snapshot = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    */
   com.google.pubsub.v1.SnapshotOrBuilder getSnapshotOrBuilder();
 
@@ -62,11 +62,12 @@ public interface UpdateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided snapshot to update.
+   * Required. Indicates which fields in the provided snapshot to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the updateMask field is set.
    */
@@ -75,11 +76,12 @@ public interface UpdateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided snapshot to update.
+   * Required. Indicates which fields in the provided snapshot to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The updateMask.
    */
@@ -88,11 +90,12 @@ public interface UpdateSnapshotRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided snapshot to update.
+   * Required. Indicates which fields in the provided snapshot to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder();
 }
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequest.java
index 17af60e84..80b4be911 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequest.java
@@ -138,10 +138,12 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The updated subscription object.
+   * Required. The updated subscription object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+   * <code>
+   * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the subscription field is set.
    */
@@ -152,10 +154,12 @@ public boolean hasSubscription() {
    *
    *
    * <pre>
-   * The updated subscription object.
+   * Required. The updated subscription object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+   * <code>
+   * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The subscription.
    */
@@ -168,10 +172,12 @@ public com.google.pubsub.v1.Subscription getSubscription() {
    *
    *
    * <pre>
-   * The updated subscription object.
+   * Required. The updated subscription object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+   * <code>
+   * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public com.google.pubsub.v1.SubscriptionOrBuilder getSubscriptionOrBuilder() {
     return getSubscription();
@@ -183,11 +189,12 @@ public com.google.pubsub.v1.SubscriptionOrBuilder getSubscriptionOrBuilder() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided subscription to update.
+   * Required. Indicates which fields in the provided subscription to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the updateMask field is set.
    */
@@ -198,11 +205,12 @@ public boolean hasUpdateMask() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided subscription to update.
+   * Required. Indicates which fields in the provided subscription to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The updateMask.
    */
@@ -213,11 +221,12 @@ public com.google.protobuf.FieldMask getUpdateMask() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided subscription to update.
+   * Required. Indicates which fields in the provided subscription to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
     return getUpdateMask();
@@ -589,10 +598,12 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return Whether the subscription field is set.
      */
@@ -603,10 +614,12 @@ public boolean hasSubscription() {
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return The subscription.
      */
@@ -623,10 +636,12 @@ public com.google.pubsub.v1.Subscription getSubscription() {
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setSubscription(com.google.pubsub.v1.Subscription value) {
       if (subscriptionBuilder_ == null) {
@@ -645,10 +660,12 @@ public Builder setSubscription(com.google.pubsub.v1.Subscription value) {
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setSubscription(com.google.pubsub.v1.Subscription.Builder builderForValue) {
       if (subscriptionBuilder_ == null) {
@@ -664,10 +681,12 @@ public Builder setSubscription(com.google.pubsub.v1.Subscription.Builder builder
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder mergeSubscription(com.google.pubsub.v1.Subscription value) {
       if (subscriptionBuilder_ == null) {
@@ -690,10 +709,12 @@ public Builder mergeSubscription(com.google.pubsub.v1.Subscription value) {
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder clearSubscription() {
       if (subscriptionBuilder_ == null) {
@@ -710,10 +731,12 @@ public Builder clearSubscription() {
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.Subscription.Builder getSubscriptionBuilder() {
 
@@ -724,10 +747,12 @@ public com.google.pubsub.v1.Subscription.Builder getSubscriptionBuilder() {
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.pubsub.v1.SubscriptionOrBuilder getSubscriptionOrBuilder() {
       if (subscriptionBuilder_ != null) {
@@ -742,10 +767,12 @@ public com.google.pubsub.v1.SubscriptionOrBuilder getSubscriptionOrBuilder() {
      *
      *
      * <pre>
-     * The updated subscription object.
+     * Required. The updated subscription object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+     * <code>
+     * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.pubsub.v1.Subscription,
@@ -774,11 +801,12 @@ public com.google.pubsub.v1.SubscriptionOrBuilder getSubscriptionOrBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return Whether the updateMask field is set.
      */
@@ -789,11 +817,12 @@ public boolean hasUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return The updateMask.
      */
@@ -810,11 +839,12 @@ public com.google.protobuf.FieldMask getUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setUpdateMask(com.google.protobuf.FieldMask value) {
       if (updateMaskBuilder_ == null) {
@@ -833,11 +863,12 @@ public Builder setUpdateMask(com.google.protobuf.FieldMask value) {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForValue) {
       if (updateMaskBuilder_ == null) {
@@ -853,11 +884,12 @@ public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForVal
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder mergeUpdateMask(com.google.protobuf.FieldMask value) {
       if (updateMaskBuilder_ == null) {
@@ -878,11 +910,12 @@ public Builder mergeUpdateMask(com.google.protobuf.FieldMask value) {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder clearUpdateMask() {
       if (updateMaskBuilder_ == null) {
@@ -899,11 +932,12 @@ public Builder clearUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.protobuf.FieldMask.Builder getUpdateMaskBuilder() {
 
@@ -914,11 +948,12 @@ public com.google.protobuf.FieldMask.Builder getUpdateMaskBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
       if (updateMaskBuilder_ != null) {
@@ -933,11 +968,12 @@ public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided subscription to update.
+     * Required. Indicates which fields in the provided subscription to update.
      * Must be specified and non-empty.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.protobuf.FieldMask,
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequestOrBuilder.java
index c2d12b0fe..730dc304b 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateSubscriptionRequestOrBuilder.java
@@ -27,10 +27,12 @@ public interface UpdateSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * The updated subscription object.
+   * Required. The updated subscription object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+   * <code>
+   * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the subscription field is set.
    */
@@ -39,10 +41,12 @@ public interface UpdateSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * The updated subscription object.
+   * Required. The updated subscription object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+   * <code>
+   * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The subscription.
    */
@@ -51,10 +55,12 @@ public interface UpdateSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * The updated subscription object.
+   * Required. The updated subscription object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Subscription subscription = 1;</code>
+   * <code>
+   * .google.pubsub.v1.Subscription subscription = 1 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   com.google.pubsub.v1.SubscriptionOrBuilder getSubscriptionOrBuilder();
 
@@ -62,11 +68,12 @@ public interface UpdateSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided subscription to update.
+   * Required. Indicates which fields in the provided subscription to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the updateMask field is set.
    */
@@ -75,11 +82,12 @@ public interface UpdateSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided subscription to update.
+   * Required. Indicates which fields in the provided subscription to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The updateMask.
    */
@@ -88,11 +96,12 @@ public interface UpdateSubscriptionRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided subscription to update.
+   * Required. Indicates which fields in the provided subscription to update.
    * Must be specified and non-empty.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder();
 }
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequest.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequest.java
index 8337a5583..d4f95780f 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequest.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequest.java
@@ -137,10 +137,10 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
    *
    *
    * <pre>
-   * The updated topic object.
+   * Required. The updated topic object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Topic topic = 1;</code>
+   * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return Whether the topic field is set.
    */
@@ -151,10 +151,10 @@ public boolean hasTopic() {
    *
    *
    * <pre>
-   * The updated topic object.
+   * Required. The updated topic object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Topic topic = 1;</code>
+   * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The topic.
    */
@@ -165,10 +165,10 @@ public com.google.pubsub.v1.Topic getTopic() {
    *
    *
    * <pre>
-   * The updated topic object.
+   * Required. The updated topic object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Topic topic = 1;</code>
+   * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    */
   public com.google.pubsub.v1.TopicOrBuilder getTopicOrBuilder() {
     return getTopic();
@@ -180,14 +180,15 @@ public com.google.pubsub.v1.TopicOrBuilder getTopicOrBuilder() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided topic to update. Must be specified
+   * Required. Indicates which fields in the provided topic to update. Must be specified
    * and non-empty. Note that if `update_mask` contains
    * "message_storage_policy" then the new value will be determined based on the
    * policy configured at the project or organization level. The
    * `message_storage_policy` must not be set in the `topic` provided above.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the updateMask field is set.
    */
@@ -198,14 +199,15 @@ public boolean hasUpdateMask() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided topic to update. Must be specified
+   * Required. Indicates which fields in the provided topic to update. Must be specified
    * and non-empty. Note that if `update_mask` contains
    * "message_storage_policy" then the new value will be determined based on the
    * policy configured at the project or organization level. The
    * `message_storage_policy` must not be set in the `topic` provided above.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The updateMask.
    */
@@ -216,14 +218,15 @@ public com.google.protobuf.FieldMask getUpdateMask() {
    *
    *
    * <pre>
-   * Indicates which fields in the provided topic to update. Must be specified
+   * Required. Indicates which fields in the provided topic to update. Must be specified
    * and non-empty. Note that if `update_mask` contains
    * "message_storage_policy" then the new value will be determined based on the
    * policy configured at the project or organization level. The
    * `message_storage_policy` must not be set in the `topic` provided above.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
     return getUpdateMask();
@@ -594,10 +597,10 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return Whether the topic field is set.
      */
@@ -608,10 +611,10 @@ public boolean hasTopic() {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      *
      * @return The topic.
      */
@@ -626,10 +629,10 @@ public com.google.pubsub.v1.Topic getTopic() {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      */
     public Builder setTopic(com.google.pubsub.v1.Topic value) {
       if (topicBuilder_ == null) {
@@ -648,10 +651,10 @@ public Builder setTopic(com.google.pubsub.v1.Topic value) {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      */
     public Builder setTopic(com.google.pubsub.v1.Topic.Builder builderForValue) {
       if (topicBuilder_ == null) {
@@ -667,10 +670,10 @@ public Builder setTopic(com.google.pubsub.v1.Topic.Builder builderForValue) {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      */
     public Builder mergeTopic(com.google.pubsub.v1.Topic value) {
       if (topicBuilder_ == null) {
@@ -690,10 +693,10 @@ public Builder mergeTopic(com.google.pubsub.v1.Topic value) {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      */
     public Builder clearTopic() {
       if (topicBuilder_ == null) {
@@ -710,10 +713,10 @@ public Builder clearTopic() {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      */
     public com.google.pubsub.v1.Topic.Builder getTopicBuilder() {
 
@@ -724,10 +727,10 @@ public com.google.pubsub.v1.Topic.Builder getTopicBuilder() {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      */
     public com.google.pubsub.v1.TopicOrBuilder getTopicOrBuilder() {
       if (topicBuilder_ != null) {
@@ -740,10 +743,10 @@ public com.google.pubsub.v1.TopicOrBuilder getTopicOrBuilder() {
      *
      *
      * <pre>
-     * The updated topic object.
+     * Required. The updated topic object.
      * </pre>
      *
-     * <code>.google.pubsub.v1.Topic topic = 1;</code>
+     * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.pubsub.v1.Topic,
@@ -771,14 +774,15 @@ public com.google.pubsub.v1.TopicOrBuilder getTopicOrBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return Whether the updateMask field is set.
      */
@@ -789,14 +793,15 @@ public boolean hasUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      *
      * @return The updateMask.
      */
@@ -813,14 +818,15 @@ public com.google.protobuf.FieldMask getUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setUpdateMask(com.google.protobuf.FieldMask value) {
       if (updateMaskBuilder_ == null) {
@@ -839,14 +845,15 @@ public Builder setUpdateMask(com.google.protobuf.FieldMask value) {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForValue) {
       if (updateMaskBuilder_ == null) {
@@ -862,14 +869,15 @@ public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForVal
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder mergeUpdateMask(com.google.protobuf.FieldMask value) {
       if (updateMaskBuilder_ == null) {
@@ -890,14 +898,15 @@ public Builder mergeUpdateMask(com.google.protobuf.FieldMask value) {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public Builder clearUpdateMask() {
       if (updateMaskBuilder_ == null) {
@@ -914,14 +923,15 @@ public Builder clearUpdateMask() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.protobuf.FieldMask.Builder getUpdateMaskBuilder() {
 
@@ -932,14 +942,15 @@ public com.google.protobuf.FieldMask.Builder getUpdateMaskBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
       if (updateMaskBuilder_ != null) {
@@ -954,14 +965,15 @@ public com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder() {
      *
      *
      * <pre>
-     * Indicates which fields in the provided topic to update. Must be specified
+     * Required. Indicates which fields in the provided topic to update. Must be specified
      * and non-empty. Note that if `update_mask` contains
      * "message_storage_policy" then the new value will be determined based on the
      * policy configured at the project or organization level. The
      * `message_storage_policy` must not be set in the `topic` provided above.
      * </pre>
      *
-     * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+     * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.protobuf.FieldMask,
diff --git a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequestOrBuilder.java b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequestOrBuilder.java
index 3599ba666..6cf4e911a 100644
--- a/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequestOrBuilder.java
+++ b/proto-google-cloud-pubsub-v1/src/main/java/com/google/pubsub/v1/UpdateTopicRequestOrBuilder.java
@@ -27,10 +27,10 @@ public interface UpdateTopicRequestOrBuilder
    *
    *
    * <pre>
-   * The updated topic object.
+   * Required. The updated topic object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Topic topic = 1;</code>
+   * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return Whether the topic field is set.
    */
@@ -39,10 +39,10 @@ public interface UpdateTopicRequestOrBuilder
    *
    *
    * <pre>
-   * The updated topic object.
+   * Required. The updated topic object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Topic topic = 1;</code>
+   * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    *
    * @return The topic.
    */
@@ -51,10 +51,10 @@ public interface UpdateTopicRequestOrBuilder
    *
    *
    * <pre>
-   * The updated topic object.
+   * Required. The updated topic object.
    * </pre>
    *
-   * <code>.google.pubsub.v1.Topic topic = 1;</code>
+   * <code>.google.pubsub.v1.Topic topic = 1 [(.google.api.field_behavior) = REQUIRED];</code>
    */
   com.google.pubsub.v1.TopicOrBuilder getTopicOrBuilder();
 
@@ -62,14 +62,15 @@ public interface UpdateTopicRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided topic to update. Must be specified
+   * Required. Indicates which fields in the provided topic to update. Must be specified
    * and non-empty. Note that if `update_mask` contains
    * "message_storage_policy" then the new value will be determined based on the
    * policy configured at the project or organization level. The
    * `message_storage_policy` must not be set in the `topic` provided above.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return Whether the updateMask field is set.
    */
@@ -78,14 +79,15 @@ public interface UpdateTopicRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided topic to update. Must be specified
+   * Required. Indicates which fields in the provided topic to update. Must be specified
    * and non-empty. Note that if `update_mask` contains
    * "message_storage_policy" then the new value will be determined based on the
    * policy configured at the project or organization level. The
    * `message_storage_policy` must not be set in the `topic` provided above.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    *
    * @return The updateMask.
    */
@@ -94,14 +96,15 @@ public interface UpdateTopicRequestOrBuilder
    *
    *
    * <pre>
-   * Indicates which fields in the provided topic to update. Must be specified
+   * Required. Indicates which fields in the provided topic to update. Must be specified
    * and non-empty. Note that if `update_mask` contains
    * "message_storage_policy" then the new value will be determined based on the
    * policy configured at the project or organization level. The
    * `message_storage_policy` must not be set in the `topic` provided above.
    * </pre>
    *
-   * <code>.google.protobuf.FieldMask update_mask = 2;</code>
+   * <code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
+   * </code>
    */
   com.google.protobuf.FieldMaskOrBuilder getUpdateMaskOrBuilder();
 }
diff --git a/proto-google-cloud-pubsub-v1/src/main/proto/google/pubsub/v1/pubsub.proto b/proto-google-cloud-pubsub-v1/src/main/proto/google/pubsub/v1/pubsub.proto
index da3801dfe..1a989b5cc 100644
--- a/proto-google-cloud-pubsub-v1/src/main/proto/google/pubsub/v1/pubsub.proto
+++ b/proto-google-cloud-pubsub-v1/src/main/proto/google/pubsub/v1/pubsub.proto
@@ -17,12 +17,14 @@ syntax = "proto3";
 
 package google.pubsub.v1;
 
-import "google/api/annotations.proto";
 import "google/api/client.proto";
+import "google/api/field_behavior.proto";
+import "google/api/resource.proto";
 import "google/protobuf/duration.proto";
 import "google/protobuf/empty.proto";
 import "google/protobuf/field_mask.proto";
 import "google/protobuf/timestamp.proto";
+import "google/api/annotations.proto";
 
 option cc_enable_arenas = true;
 option csharp_namespace = "Google.Cloud.PubSub.V1";
@@ -49,6 +51,7 @@ service Publisher {
       put: "/v1/{name=projects/*/topics/*}"
       body: "*"
     };
+    option (google.api.method_signature) = "name";
   }
 
   // Updates an existing topic. Note that certain properties of a
@@ -67,6 +70,7 @@ service Publisher {
       post: "/v1/{topic=projects/*/topics/*}:publish"
       body: "*"
     };
+    option (google.api.method_signature) = "topic,messages";
   }
 
   // Gets the configuration of a topic.
@@ -74,6 +78,7 @@ service Publisher {
     option (google.api.http) = {
       get: "/v1/{topic=projects/*/topics/*}"
     };
+    option (google.api.method_signature) = "topic";
   }
 
   // Lists matching topics.
@@ -81,14 +86,15 @@ service Publisher {
     option (google.api.http) = {
       get: "/v1/{project=projects/*}/topics"
     };
+    option (google.api.method_signature) = "project";
   }
 
   // Lists the names of the subscriptions on this topic.
-  rpc ListTopicSubscriptions(ListTopicSubscriptionsRequest)
-      returns (ListTopicSubscriptionsResponse) {
+  rpc ListTopicSubscriptions(ListTopicSubscriptionsRequest) returns (ListTopicSubscriptionsResponse) {
     option (google.api.http) = {
       get: "/v1/{topic=projects/*/topics/*}/subscriptions"
     };
+    option (google.api.method_signature) = "topic";
   }
 
   // Lists the names of the snapshots on this topic. Snapshots are used in
@@ -97,8 +103,7 @@ service Publisher {
   // you to manage message acknowledgments in bulk. That is, you can set the
   // acknowledgment state of messages in an existing subscription to the state
   // captured by a snapshot.
-  rpc ListTopicSnapshots(ListTopicSnapshotsRequest)
-      returns (ListTopicSnapshotsResponse) {
+  rpc ListTopicSnapshots(ListTopicSnapshotsRequest) returns (ListTopicSnapshotsResponse) {
     option (google.api.http) = {
       get: "/v1/{topic=projects/*/topics/*}/snapshots"
     };
@@ -113,6 +118,7 @@ service Publisher {
     option (google.api.http) = {
       delete: "/v1/{topic=projects/*/topics/*}"
     };
+    option (google.api.method_signature) = "topic";
   }
 }
 
@@ -127,13 +133,19 @@ message MessageStoragePolicy {
 
 // A topic resource.
 message Topic {
-  // The name of the topic. It must have the format
+  option (google.api.resource) = {
+    type: "pubsub.googleapis.com/Topic"
+    pattern: "projects/{project}/topics/{topic}"
+    pattern: "_deleted-topic_"
+  };
+
+  // Required. The name of the topic. It must have the format
   // `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
   // and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
   // underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
   // signs (`%`). It must be between 3 and 255 characters in length, and it
   // must not start with `"goog"`.
-  string name = 1;
+  string name = 1 [(google.api.field_behavior) = REQUIRED];
 
   // See <a href="https://cloud.google.com/pubsub/docs/labels"> Creating and
   // managing labels</a>.
@@ -193,32 +205,42 @@ message PubsubMessage {
 
 // Request for the GetTopic method.
 message GetTopicRequest {
-  // The name of the topic to get.
+  // Required. The name of the topic to get.
   // Format is `projects/{project}/topics/{topic}`.
-  string topic = 1;
+  string topic = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Topic"
+    }
+  ];
 }
 
 // Request for the UpdateTopic method.
 message UpdateTopicRequest {
-  // The updated topic object.
-  Topic topic = 1;
+  // Required. The updated topic object.
+  Topic topic = 1 [(google.api.field_behavior) = REQUIRED];
 
-  // Indicates which fields in the provided topic to update. Must be specified
+  // Required. Indicates which fields in the provided topic to update. Must be specified
   // and non-empty. Note that if `update_mask` contains
   // "message_storage_policy" then the new value will be determined based on the
   // policy configured at the project or organization level. The
   // `message_storage_policy` must not be set in the `topic` provided above.
-  google.protobuf.FieldMask update_mask = 2;
+  google.protobuf.FieldMask update_mask = 2 [(google.api.field_behavior) = REQUIRED];
 }
 
 // Request for the Publish method.
 message PublishRequest {
-  // The messages in the request will be published on this topic.
+  // Required. The messages in the request will be published on this topic.
   // Format is `projects/{project}/topics/{topic}`.
-  string topic = 1;
-
-  // The messages to publish.
-  repeated PubsubMessage messages = 2;
+  string topic = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Topic"
+    }
+  ];
+
+  // Required. The messages to publish.
+  repeated PubsubMessage messages = 2 [(google.api.field_behavior) = REQUIRED];
 }
 
 // Response for the `Publish` method.
@@ -231,9 +253,14 @@ message PublishResponse {
 
 // Request for the `ListTopics` method.
 message ListTopicsRequest {
-  // The name of the project in which to list topics.
+  // Required. The name of the project in which to list topics.
   // Format is `projects/{project-id}`.
-  string project = 1;
+  string project = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "cloudresourcemanager.googleapis.com/Project"
+    }
+  ];
 
   // Maximum number of topics to return.
   int32 page_size = 2;
@@ -256,9 +283,14 @@ message ListTopicsResponse {
 
 // Request for the `ListTopicSubscriptions` method.
 message ListTopicSubscriptionsRequest {
-  // The name of the topic that subscriptions are attached to.
+  // Required. The name of the topic that subscriptions are attached to.
   // Format is `projects/{project}/topics/{topic}`.
-  string topic = 1;
+  string topic = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Topic"
+    }
+  ];
 
   // Maximum number of subscription names to return.
   int32 page_size = 2;
@@ -272,7 +304,9 @@ message ListTopicSubscriptionsRequest {
 // Response for the `ListTopicSubscriptions` method.
 message ListTopicSubscriptionsResponse {
   // The names of the subscriptions that match the request.
-  repeated string subscriptions = 1;
+  repeated string subscriptions = 1 [(google.api.resource_reference) = {
+                                       type: "pubsub.googleapis.com/Subscription"
+                                     }];
 
   // If not empty, indicates that there may be more subscriptions that match
   // the request; this value should be passed in a new
@@ -308,9 +342,14 @@ message ListTopicSnapshotsResponse {
 
 // Request for the `DeleteTopic` method.
 message DeleteTopicRequest {
-  // Name of the topic to delete.
+  // Required. Name of the topic to delete.
   // Format is `projects/{project}/topics/{topic}`.
-  string topic = 1;
+  string topic = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Topic"
+    }
+  ];
 }
 
 // The service that an application uses to manipulate subscriptions and to
@@ -340,6 +379,7 @@ service Subscriber {
       put: "/v1/{name=projects/*/subscriptions/*}"
       body: "*"
     };
+    option (google.api.method_signature) = "name,topic,push_config,ack_deadline_seconds";
   }
 
   // Gets the configuration details of a subscription.
@@ -347,6 +387,7 @@ service Subscriber {
     option (google.api.http) = {
       get: "/v1/{subscription=projects/*/subscriptions/*}"
     };
+    option (google.api.method_signature) = "subscription";
   }
 
   // Updates an existing subscription. Note that certain properties of a
@@ -359,11 +400,11 @@ service Subscriber {
   }
 
   // Lists matching subscriptions.
-  rpc ListSubscriptions(ListSubscriptionsRequest)
-      returns (ListSubscriptionsResponse) {
+  rpc ListSubscriptions(ListSubscriptionsRequest) returns (ListSubscriptionsResponse) {
     option (google.api.http) = {
       get: "/v1/{project=projects/*}/subscriptions"
     };
+    option (google.api.method_signature) = "project";
   }
 
   // Deletes an existing subscription. All messages retained in the subscription
@@ -371,11 +412,11 @@ service Subscriber {
   // `NOT_FOUND`. After a subscription is deleted, a new one may be created with
   // the same name, but the new one has no association with the old
   // subscription or its topic unless the same topic is specified.
-  rpc DeleteSubscription(DeleteSubscriptionRequest)
-      returns (google.protobuf.Empty) {
+  rpc DeleteSubscription(DeleteSubscriptionRequest) returns (google.protobuf.Empty) {
     option (google.api.http) = {
       delete: "/v1/{subscription=projects/*/subscriptions/*}"
     };
+    option (google.api.method_signature) = "subscription";
   }
 
   // Modifies the ack deadline for a specific message. This method is useful
@@ -383,12 +424,12 @@ service Subscriber {
   // subscriber, or to make the message available for redelivery if the
   // processing was interrupted. Note that this does not modify the
   // subscription-level `ackDeadlineSeconds` used for subsequent messages.
-  rpc ModifyAckDeadline(ModifyAckDeadlineRequest)
-      returns (google.protobuf.Empty) {
+  rpc ModifyAckDeadline(ModifyAckDeadlineRequest) returns (google.protobuf.Empty) {
     option (google.api.http) = {
       post: "/v1/{subscription=projects/*/subscriptions/*}:modifyAckDeadline"
       body: "*"
     };
+    option (google.api.method_signature) = "subscription,ack_ids,ack_deadline_seconds";
   }
 
   // Acknowledges the messages associated with the `ack_ids` in the
@@ -403,6 +444,7 @@ service Subscriber {
       post: "/v1/{subscription=projects/*/subscriptions/*}:acknowledge"
       body: "*"
     };
+    option (google.api.method_signature) = "subscription,ack_ids";
   }
 
   // Pulls messages from the server. The server may return `UNAVAILABLE` if
@@ -413,6 +455,7 @@ service Subscriber {
       post: "/v1/{subscription=projects/*/subscriptions/*}:pull"
       body: "*"
     };
+    option (google.api.method_signature) = "subscription,return_immediately,max_messages";
   }
 
   // Establishes a stream with the server, which sends messages down to the
@@ -422,8 +465,8 @@ service Subscriber {
   // reassign server-side resources, in which case, the client should
   // re-establish the stream. Flow control can be achieved by configuring the
   // underlying RPC channel.
-  rpc StreamingPull(stream StreamingPullRequest)
-      returns (stream StreamingPullResponse) {}
+  rpc StreamingPull(stream StreamingPullRequest) returns (stream StreamingPullResponse) {
+  }
 
   // Modifies the `PushConfig` for a specified subscription.
   //
@@ -431,12 +474,12 @@ service Subscriber {
   // an empty `PushConfig`) or vice versa, or change the endpoint URL and other
   // attributes of a push subscription. Messages will accumulate for delivery
   // continuously through the call regardless of changes to the `PushConfig`.
-  rpc ModifyPushConfig(ModifyPushConfigRequest)
-      returns (google.protobuf.Empty) {
+  rpc ModifyPushConfig(ModifyPushConfigRequest) returns (google.protobuf.Empty) {
     option (google.api.http) = {
       post: "/v1/{subscription=projects/*/subscriptions/*}:modifyPushConfig"
       body: "*"
     };
+    option (google.api.method_signature) = "subscription,push_config";
   }
 
   // Gets the configuration details of a snapshot. Snapshots are used in
@@ -460,6 +503,7 @@ service Subscriber {
     option (google.api.http) = {
       get: "/v1/{project=projects/*}/snapshots"
     };
+    option (google.api.method_signature) = "project";
   }
 
   // Creates a snapshot from the requested subscription. Snapshots are used in
@@ -485,6 +529,7 @@ service Subscriber {
       put: "/v1/{name=projects/*/snapshots/*}"
       body: "*"
     };
+    option (google.api.method_signature) = "name,subscription";
   }
 
   // Updates an existing snapshot. Snapshots are used in
@@ -514,6 +559,7 @@ service Subscriber {
     option (google.api.http) = {
       delete: "/v1/{snapshot=projects/*/snapshots/*}"
     };
+    option (google.api.method_signature) = "snapshot";
   }
 
   // Seeks an existing subscription to a point in time or to a given snapshot,
@@ -534,19 +580,29 @@ service Subscriber {
 
 // A subscription resource.
 message Subscription {
-  // The name of the subscription. It must have the format
+  option (google.api.resource) = {
+    type: "pubsub.googleapis.com/Subscription"
+    pattern: "projects/{project}/subscriptions/{subscription}"
+  };
+
+  // Required. The name of the subscription. It must have the format
   // `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
   // start with a letter, and contain only letters (`[A-Za-z]`), numbers
   // (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
   // plus (`+`) or percent signs (`%`). It must be between 3 and 255 characters
   // in length, and it must not start with `"goog"`.
-  string name = 1;
+  string name = 1 [(google.api.field_behavior) = REQUIRED];
 
-  // The name of the topic from which this subscription is receiving messages.
+  // Required. The name of the topic from which this subscription is receiving messages.
   // Format is `projects/{project}/topics/{topic}`.
   // The value of this field will be `_deleted-topic_` if the topic has been
   // deleted.
-  string topic = 2;
+  string topic = 2 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Topic"
+    }
+  ];
 
   // If push delivery is used with this subscription, this field is
   // used to configure it. An empty `pushConfig` signifies that the subscriber
@@ -762,26 +818,36 @@ message ReceivedMessage {
 
 // Request for the GetSubscription method.
 message GetSubscriptionRequest {
-  // The name of the subscription to get.
+  // Required. The name of the subscription to get.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 1;
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
 }
 
 // Request for the UpdateSubscription method.
 message UpdateSubscriptionRequest {
-  // The updated subscription object.
-  Subscription subscription = 1;
+  // Required. The updated subscription object.
+  Subscription subscription = 1 [(google.api.field_behavior) = REQUIRED];
 
-  // Indicates which fields in the provided subscription to update.
+  // Required. Indicates which fields in the provided subscription to update.
   // Must be specified and non-empty.
-  google.protobuf.FieldMask update_mask = 2;
+  google.protobuf.FieldMask update_mask = 2 [(google.api.field_behavior) = REQUIRED];
 }
 
 // Request for the `ListSubscriptions` method.
 message ListSubscriptionsRequest {
-  // The name of the project in which to list subscriptions.
+  // Required. The name of the project in which to list subscriptions.
   // Format is `projects/{project-id}`.
-  string project = 1;
+  string project = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "cloudresourcemanager.googleapis.com/Project"
+    }
+  ];
 
   // Maximum number of subscriptions to return.
   int32 page_size = 2;
@@ -805,31 +871,46 @@ message ListSubscriptionsResponse {
 
 // Request for the DeleteSubscription method.
 message DeleteSubscriptionRequest {
-  // The subscription to delete.
+  // Required. The subscription to delete.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 1;
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
 }
 
 // Request for the ModifyPushConfig method.
 message ModifyPushConfigRequest {
-  // The name of the subscription.
+  // Required. The name of the subscription.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 1;
-
-  // The push configuration for future deliveries.
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
+
+  // Required. The push configuration for future deliveries.
   //
   // An empty `pushConfig` indicates that the Pub/Sub system should
   // stop pushing messages from the given subscription and allow
   // messages to be pulled and acknowledged - effectively pausing
   // the subscription if `Pull` or `StreamingPull` is not called.
-  PushConfig push_config = 2;
+  PushConfig push_config = 2 [(google.api.field_behavior) = REQUIRED];
 }
 
 // Request for the `Pull` method.
 message PullRequest {
-  // The subscription from which messages should be pulled.
+  // Required. The subscription from which messages should be pulled.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 1;
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
 
   // If this field set to true, the system will respond immediately even if
   // it there are no messages available to return in the `Pull` response.
@@ -837,10 +918,10 @@ message PullRequest {
   // least one message is available, rather than returning no messages.
   bool return_immediately = 2;
 
-  // The maximum number of messages to return for this request. Must be a
+  // Required. The maximum number of messages to return for this request. Must be a
   // positive integer. The Pub/Sub system may return fewer than the number
   // specified.
-  int32 max_messages = 3;
+  int32 max_messages = 3 [(google.api.field_behavior) = REQUIRED];
 }
 
 // Response for the `Pull` method.
@@ -854,14 +935,19 @@ message PullResponse {
 
 // Request for the ModifyAckDeadline method.
 message ModifyAckDeadlineRequest {
-  // The name of the subscription.
+  // Required. The name of the subscription.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 1;
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
 
-  // List of acknowledgment IDs.
-  repeated string ack_ids = 4;
+  // Required. List of acknowledgment IDs.
+  repeated string ack_ids = 4 [(google.api.field_behavior) = REQUIRED];
 
-  // The new ack deadline with respect to the time this request was sent to
+  // Required. The new ack deadline with respect to the time this request was sent to
   // the Pub/Sub system. For example, if the value is 10, the new
   // ack deadline will expire 10 seconds after the `ModifyAckDeadline` call
   // was made. Specifying zero might immediately make the message available for
@@ -869,29 +955,39 @@ message ModifyAckDeadlineRequest {
   // increase in the rate of message redeliveries (that is, duplicates).
   // The minimum deadline you can specify is 0 seconds.
   // The maximum deadline you can specify is 600 seconds (10 minutes).
-  int32 ack_deadline_seconds = 3;
+  int32 ack_deadline_seconds = 3 [(google.api.field_behavior) = REQUIRED];
 }
 
 // Request for the Acknowledge method.
 message AcknowledgeRequest {
-  // The subscription whose message is being acknowledged.
+  // Required. The subscription whose message is being acknowledged.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 1;
-
-  // The acknowledgment ID for the messages being acknowledged that was returned
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
+
+  // Required. The acknowledgment ID for the messages being acknowledged that was returned
   // by the Pub/Sub system in the `Pull` response. Must not be empty.
-  repeated string ack_ids = 2;
+  repeated string ack_ids = 2 [(google.api.field_behavior) = REQUIRED];
 }
 
 // Request for the `StreamingPull` streaming RPC method. This request is used to
 // establish the initial stream as well as to stream acknowledgements and ack
 // deadline modifications from the client to the server.
 message StreamingPullRequest {
-  // The subscription for which to initialize the new stream. This must be
+  // Required. The subscription for which to initialize the new stream. This must be
   // provided in the first request on the stream, and must not be set in
   // subsequent requests from client to server.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 1;
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
 
   // List of acknowledgement IDs for acknowledging previously received messages
   // (received on this stream or a different stream). If an ack ID has expired,
@@ -920,11 +1016,11 @@ message StreamingPullRequest {
   // processing was interrupted.
   repeated string modify_deadline_ack_ids = 4;
 
-  // The ack deadline to use for the stream. This must be provided in the
+  // Required. The ack deadline to use for the stream. This must be provided in the
   // first request on the stream, but it can also be updated on subsequent
   // requests from client to server. The minimum deadline you can specify is 10
   // seconds. The maximum deadline you can specify is 600 seconds (10 minutes).
-  int32 stream_ack_deadline_seconds = 5;
+  int32 stream_ack_deadline_seconds = 5 [(google.api.field_behavior) = REQUIRED];
 
   // A unique identifier that is used to distinguish client instances from each
   // other. Only needs to be provided on the initial request. When a stream
@@ -944,15 +1040,20 @@ message StreamingPullResponse {
 
 // Request for the `CreateSnapshot` method.
 message CreateSnapshotRequest {
-  // User-provided name for this snapshot. If the name is not provided in the
+  // Required. User-provided name for this snapshot. If the name is not provided in the
   // request, the server will assign a random name for this snapshot on the same
   // project as the subscription. Note that for REST API requests, you must
   // specify a name.  See the <a
   // href="https://cloud.google.com/pubsub/docs/admin#resource_names"> resource
   // name rules</a>. Format is `projects/{project}/snapshots/{snap}`.
-  string name = 1;
-
-  // The subscription whose backlog the snapshot retains.
+  string name = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Snapshot"
+    }
+  ];
+
+  // Required. The subscription whose backlog the snapshot retains.
   // Specifically, the created snapshot is guaranteed to retain:
   //  (a) The existing backlog on the subscription. More precisely, this is
   //      defined as the messages in the subscription's backlog that are
@@ -961,7 +1062,12 @@ message CreateSnapshotRequest {
   //  (b) Any messages published to the subscription's topic following the
   //      successful completion of the CreateSnapshot request.
   // Format is `projects/{project}/subscriptions/{sub}`.
-  string subscription = 2;
+  string subscription = 2 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
 
   // See <a href="https://cloud.google.com/pubsub/docs/labels"> Creating and
   // managing labels</a>.
@@ -970,12 +1076,12 @@ message CreateSnapshotRequest {
 
 // Request for the UpdateSnapshot method.
 message UpdateSnapshotRequest {
-  // The updated snapshot object.
-  Snapshot snapshot = 1;
+  // Required. The updated snapshot object.
+  Snapshot snapshot = 1 [(google.api.field_behavior) = REQUIRED];
 
-  // Indicates which fields in the provided snapshot to update.
+  // Required. Indicates which fields in the provided snapshot to update.
   // Must be specified and non-empty.
-  google.protobuf.FieldMask update_mask = 2;
+  google.protobuf.FieldMask update_mask = 2 [(google.api.field_behavior) = REQUIRED];
 }
 
 // A snapshot resource. Snapshots are used in
@@ -985,11 +1091,18 @@ message UpdateSnapshotRequest {
 // acknowledgment state of messages in an existing subscription to the state
 // captured by a snapshot.
 message Snapshot {
+  option (google.api.resource) = {
+    type: "pubsub.googleapis.com/Snapshot"
+    pattern: "projects/{project}/snapshots/{snapshot}"
+  };
+
   // The name of the snapshot.
   string name = 1;
 
   // The name of the topic from which this snapshot is retaining messages.
-  string topic = 2;
+  string topic = 2 [(google.api.resource_reference) = {
+                      type: "pubsub.googleapis.com/Topic"
+                    }];
 
   // The snapshot is guaranteed to exist up until this time.
   // A newly-created snapshot expires no later than 7 days from the time of its
@@ -1010,16 +1123,26 @@ message Snapshot {
 
 // Request for the GetSnapshot method.
 message GetSnapshotRequest {
-  // The name of the snapshot to get.
+  // Required. The name of the snapshot to get.
   // Format is `projects/{project}/snapshots/{snap}`.
-  string snapshot = 1;
+  string snapshot = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Snapshot"
+    }
+  ];
 }
 
 // Request for the `ListSnapshots` method.
 message ListSnapshotsRequest {
-  // The name of the project in which to list snapshots.
+  // Required. The name of the project in which to list snapshots.
   // Format is `projects/{project-id}`.
-  string project = 1;
+  string project = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "cloudresourcemanager.googleapis.com/Project"
+    }
+  ];
 
   // Maximum number of snapshots to return.
   int32 page_size = 2;
@@ -1042,15 +1165,25 @@ message ListSnapshotsResponse {
 
 // Request for the `DeleteSnapshot` method.
 message DeleteSnapshotRequest {
-  // The name of the snapshot to delete.
+  // Required. The name of the snapshot to delete.
   // Format is `projects/{project}/snapshots/{snap}`.
-  string snapshot = 1;
+  string snapshot = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Snapshot"
+    }
+  ];
 }
 
 // Request for the `Seek` method.
 message SeekRequest {
-  // The subscription to affect.
-  string subscription = 1;
+  // Required. The subscription to affect.
+  string subscription = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.resource_reference) = {
+      type: "pubsub.googleapis.com/Subscription"
+    }
+  ];
 
   oneof target {
     // The time to seek to.
@@ -1069,9 +1202,13 @@ message SeekRequest {
     // The snapshot to seek to. The snapshot's topic must be the same as that of
     // the provided subscription.
     // Format is `projects/{project}/snapshots/{snap}`.
-    string snapshot = 3;
+    string snapshot = 3 [(google.api.resource_reference) = {
+                           type: "pubsub.googleapis.com/Snapshot"
+                         }];
   }
 }
 
 // Response for the `Seek` method (this response is empty).
-message SeekResponse {}
+message SeekResponse {
+
+}
diff --git a/synth.metadata b/synth.metadata
index 89f33cfa5..a8889c0aa 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -1,6 +1,20 @@
 {
-  "updateTime": "2020-02-08T10:00:19.164940Z",
+  "updateTime": "2020-02-14T22:58:09.670476Z",
   "sources": [
+    {
+      "git": {
+        "name": ".",
+        "remote": "https://github.com/googleapis/java-pubsub.git",
+        "sha": "20293d1c984f17759f5bed527c9a5b1f74d47dc4"
+      }
+    },
+    {
+      "git": {
+        "name": "synthtool",
+        "remote": "rpc://devrel/cloud/libraries/tools/autosynth",
+        "sha": "dd7cd93888cbeb1d4c56a1ca814491c7813160e8"
+      }
+    },
     {
       "generator": {
         "name": "artman",
@@ -12,9 +26,9 @@
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "e7d8a694f4559201e6913f6610069cb08b39274e",
-        "internalRef": "293903652",
-        "log": "e7d8a694f4559201e6913f6610069cb08b39274e\nDepend on the latest gapic-generator and resource names plugin.\n\nThis fixes the very old an very annoying bug: https://github.com/googleapis/gapic-generator/pull/3087\n\nPiperOrigin-RevId: 293903652\n\n806b2854a966d55374ee26bb0cef4e30eda17b58\nfix: correct capitalization of Ruby namespaces in SecurityCenter V1p1beta1\n\nPiperOrigin-RevId: 293903613\n\n1b83c92462b14d67a7644e2980f723112472e03a\nPublish annotations and grpc service config for Logging API.\n\nPiperOrigin-RevId: 293893514\n\ne46f761cd6ec15a9e3d5ed4ff321a4bcba8e8585\nGenerate the Bazel build file for recommendengine public api\n\nPiperOrigin-RevId: 293710856\n\n68477017c4173c98addac0373950c6aa9d7b375f\nMake `language_code` optional for UpdateIntentRequest and BatchUpdateIntentsRequest.\n\nThe comments and proto annotations describe this parameter as optional.\n\nPiperOrigin-RevId: 293703548\n\n16f823f578bca4e845a19b88bb9bc5870ea71ab2\nAdd BUILD.bazel files for managedidentities API\n\nPiperOrigin-RevId: 293698246\n\n2f53fd8178c9a9de4ad10fae8dd17a7ba36133f2\nAdd v1p1beta1 config file\n\nPiperOrigin-RevId: 293696729\n\n052b274138fce2be80f97b6dcb83ab343c7c8812\nAdd source field for user event and add field behavior annotations\n\nPiperOrigin-RevId: 293693115\n\n1e89732b2d69151b1b3418fff3d4cc0434f0dded\ndatacatalog: v1beta1 add three new RPCs to gapic v1beta1 config\n\nPiperOrigin-RevId: 293692823\n\n9c8bd09bbdc7c4160a44f1fbab279b73cd7a2337\nchange the name of AccessApproval service to AccessApprovalAdmin\n\nPiperOrigin-RevId: 293690934\n\n2e23b8fbc45f5d9e200572ca662fe1271bcd6760\nAdd ListEntryGroups method, add http bindings to support entry group tagging, and update some comments.\n\nPiperOrigin-RevId: 293666452\n\n0275e38a4ca03a13d3f47a9613aac8c8b0d3f1f2\nAdd proto_package field to managedidentities API. It is needed for APIs that still depend on artman generation.\n\nPiperOrigin-RevId: 293643323\n\n4cdfe8278cb6f308106580d70648001c9146e759\nRegenerating public protos for Data Catalog to add new Custom Type Entry feature.\n\nPiperOrigin-RevId: 293614782\n\n45d2a569ab526a1fad3720f95eefb1c7330eaada\nEnable client generation for v1 ManagedIdentities API.\n\nPiperOrigin-RevId: 293515675\n\n2c17086b77e6f3bcf04a1f65758dfb0c3da1568f\nAdd the Actions on Google common types (//google/actions/type/*).\n\nPiperOrigin-RevId: 293478245\n\n781aadb932e64a12fb6ead7cd842698d99588433\nDialogflow weekly v2/v2beta1 library update:\n- Documentation updates\nImportant updates are also posted at\nhttps://cloud.google.com/dialogflow/docs/release-notes\n\nPiperOrigin-RevId: 293443396\n\ne2602608c9138c2fca24162720e67f9307c30b95\nDialogflow weekly v2/v2beta1 library update:\n- Documentation updates\nImportant updates are also posted at\nhttps://cloud.google.com/dialogflow/docs/release-notes\n\nPiperOrigin-RevId: 293442964\n\nc8aef82028d06b7992278fa9294c18570dc86c3d\nAdd cc_proto_library and cc_grpc_library targets for Bigtable protos.\n\nAlso fix indentation of cc_grpc_library targets in Spanner and IAM protos.\n\nPiperOrigin-RevId: 293440538\n\ne2faab04f4cb7f9755072330866689b1943a16e9\ncloudtasks: v2 replace non-standard retry params in gapic config v2\n\nPiperOrigin-RevId: 293424055\n\ndfb4097ea628a8470292c6590a4313aee0c675bd\nerrorreporting: v1beta1 add legacy artman config for php\n\nPiperOrigin-RevId: 293423790\n\nb18aed55b45bfe5b62476292c72759e6c3e573c6\nasset: v1p1beta1 updated comment for `page_size` limit.\n\nPiperOrigin-RevId: 293421386\n\nc9ef36b7956d9859a2fc86ad35fcaa16958ab44f\nbazel: Refactor CI build scripts\n\nPiperOrigin-RevId: 293387911\n\na8ed9d921fdddc61d8467bfd7c1668f0ad90435c\nfix: set Ruby module name for OrgPolicy\n\nPiperOrigin-RevId: 293257997\n\n6c7d28509bd8315de8af0889688ee20099594269\nredis: v1beta1 add UpgradeInstance and connect_mode field to Instance\n\nPiperOrigin-RevId: 293242878\n\nae0abed4fcb4c21f5cb67a82349a049524c4ef68\nredis: v1 add connect_mode field to Instance\n\nPiperOrigin-RevId: 293241914\n\n3f7a0d29b28ee9365771da2b66edf7fa2b4e9c56\nAdds service config definition for bigqueryreservation v1beta1\n\nPiperOrigin-RevId: 293234418\n\n0c88168d5ed6fe353a8cf8cbdc6bf084f6bb66a5\naddition of BUILD & configuration for accessapproval v1\n\nPiperOrigin-RevId: 293219198\n\n39bedc2e30f4778ce81193f6ba1fec56107bcfc4\naccessapproval: v1 publish protos\n\nPiperOrigin-RevId: 293167048\n\n69d9945330a5721cd679f17331a78850e2618226\nAdd file-level `Session` resource definition\n\nPiperOrigin-RevId: 293080182\n\nf6a1a6b417f39694275ca286110bc3c1ca4db0dc\nAdd file-level `Session` resource definition\n\nPiperOrigin-RevId: 293080178\n\n29d40b78e3dc1579b0b209463fbcb76e5767f72a\nExpose managedidentities/v1beta1/ API for client library usage.\n\nPiperOrigin-RevId: 292979741\n\na22129a1fb6e18056d576dfb7717aef74b63734a\nExpose managedidentities/v1/ API for client library usage.\n\nPiperOrigin-RevId: 292968186\n\n"
+        "sha": "d9835e922ea79eed8497db270d2f9f85099a519c",
+        "internalRef": "295185610",
+        "log": "d9835e922ea79eed8497db270d2f9f85099a519c\nUpdate some minor docs changes about user event proto\n\nPiperOrigin-RevId: 295185610\n\n5f311e416e69c170243de722023b22f3df89ec1c\nfix: use correct PHP package name in gapic configuration\n\nPiperOrigin-RevId: 295161330\n\n6cdd74dcdb071694da6a6b5a206e3a320b62dd11\npubsub: v1 add client config annotations and retry config\n\nPiperOrigin-RevId: 295158776\n\n5169f46d9f792e2934d9fa25c36d0515b4fd0024\nAdded cloud asset api v1p4beta1.\n\nPiperOrigin-RevId: 295026522\n\n56b55aa8818cd0a532a7d779f6ef337ba809ccbd\nFix: Resource annotations for CreateTimeSeriesRequest and ListTimeSeriesRequest should refer to valid resources. TimeSeries is not a named resource.\n\nPiperOrigin-RevId: 294931650\n\n0646bc775203077226c2c34d3e4d50cc4ec53660\nRemove unnecessary languages from bigquery-related artman configuration files.\n\nPiperOrigin-RevId: 294809380\n\n8b78aa04382e3d4147112ad6d344666771bb1909\nUpdate backend.proto for schemes and protocol\n\nPiperOrigin-RevId: 294788800\n\n80b8f8b3de2359831295e24e5238641a38d8488f\nAdds artman config files for bigquerystorage endpoints v1beta2, v1alpha2, v1\n\nPiperOrigin-RevId: 294763931\n\n2c17ac33b226194041155bb5340c3f34733f1b3a\nAdd parameter to sample generated for UpdateInstance. Related to https://github.com/googleapis/python-redis/issues/4\n\nPiperOrigin-RevId: 294734008\n\nd5e8a8953f2acdfe96fb15e85eb2f33739623957\nMove bigquery datatransfer to gapic v2.\n\nPiperOrigin-RevId: 294703703\n\nefd36705972cfcd7d00ab4c6dfa1135bafacd4ae\nfix: Add two annotations that we missed.\n\nPiperOrigin-RevId: 294664231\n\n8a36b928873ff9c05b43859b9d4ea14cd205df57\nFix: Define the \"bigquery.googleapis.com/Table\" resource in the BigQuery Storage API (v1beta2).\n\nPiperOrigin-RevId: 294459768\n\nc7a3caa2c40c49f034a3c11079dd90eb24987047\nFix: Define the \"bigquery.googleapis.com/Table\" resource in the BigQuery Storage API (v1).\n\nPiperOrigin-RevId: 294456889\n\n5006247aa157e59118833658084345ee59af7c09\nFix: Make deprecated fields optional\nFix: Deprecate SetLoggingServiceRequest.zone in line with the comments\nFeature: Add resource name method signatures where appropriate\n\nPiperOrigin-RevId: 294383128\n\neabba40dac05c5cbe0fca3a35761b17e372036c4\nFix: C# and PHP package/namespace capitalization for BigQuery Storage v1.\n\nPiperOrigin-RevId: 294382444\n\nf8d9a858a7a55eba8009a23aa3f5cc5fe5e88dde\nfix: artman configuration file for bigtable-admin\n\nPiperOrigin-RevId: 294322616\n\n0f29555d1cfcf96add5c0b16b089235afbe9b1a9\nAPI definition for (not-yet-launched) GCS gRPC.\n\nPiperOrigin-RevId: 294321472\n\nfcc86bee0e84dc11e9abbff8d7c3529c0626f390\nfix: Bigtable Admin v2\n\nChange LRO metadata from PartialUpdateInstanceMetadata\nto UpdateInstanceMetadata. (Otherwise, it will not build.)\n\nPiperOrigin-RevId: 294264582\n\n6d9361eae2ebb3f42d8c7ce5baf4bab966fee7c0\nrefactor: Add annotations to Bigtable Admin v2.\n\nPiperOrigin-RevId: 294243406\n\nad7616f3fc8e123451c8b3a7987bc91cea9e6913\nFix: Resource type in CreateLogMetricRequest should use logging.googleapis.com.\nFix: ListLogEntries should have a method signature for convenience of calling it.\n\nPiperOrigin-RevId: 294222165\n\n63796fcbb08712676069e20a3e455c9f7aa21026\nFix: Remove extraneous resource definition for cloudkms.googleapis.com/CryptoKey.\n\nPiperOrigin-RevId: 294176658\n\n"
       }
     },
     {