clean up

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/BigtableDataSettings.java

@@ -490,7 +490,7 @@ public Builder enableBuiltinMetrics() throws IOException {
                 .setProjectId(stubSettings.getProjectId())
                 .setMonitoredResource(
                     MonitoredResource.newBuilder().setType("bigtable_table").build())
-                .setMetricNamePrefix("bigtable.googleapis.com/client/")
+                .setMetricNamePrefix("bigtable.googleapis.com/internal/client/")
                 .setExportInterval(
                     com.google.bigtable.veneer.repackaged.io.opencensus.common.Duration.create(
                         10, 0))

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/EnhancedBigtableStub.java

@@ -146,6 +146,7 @@ public class EnhancedBigtableStub implements AutoCloseable {
   public static EnhancedBigtableStub create(EnhancedBigtableStubSettings settings)
       throws IOException {
     settings = finalizeSettings(settings, Tags.getTagger(), Stats.getStatsRecorder());
+
     return new EnhancedBigtableStub(settings, ClientContext.create(settings));
   }
 

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/metrics/BigtableTracerStreamingCallable.java

@@ -36,6 +36,8 @@
  *
  * <p>- Call {@link BigtableTracer#onRequest()} to record the request events in a stream.
  *
+ * <p>- Get Bigtable zone and cluster information from response trailer and record in tracer.
+ *
  * <p>This class is considered an internal implementation detail and not meant to be used by
  * applications.
  */

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/metrics/BigtableTracerUnaryCallable.java

@@ -28,11 +28,15 @@
 import javax.annotation.Nonnull;
 
 /**
- * This callable will inject a {@link GrpcResponseMetadata} to access the headers and trailers
- * returned by gRPC methods upon completion. The {@link BigtableTracer} will process metrics that
- * were injected in the header/trailer and publish them to OpenCensus. If {@link
- * GrpcResponseMetadata#getMetadata()} returned null, it probably means that the request has never
- * reached GFE, and it'll increment the gfe_header_missing_counter in this case.
+ * This callable will:
+ *
+ * <p>- Inject a {@link GrpcResponseMetadata} to access the headers and trailers returned by gRPC
+ * methods upon completion. The {@link BigtableTracer} will process metrics that were injected in
+ * the header/trailer and publish them to OpenCensus. If {@link GrpcResponseMetadata#getMetadata()}
+ * returned null, it probably means that the request has never reached GFE, and it'll increment the
+ * gfe_header_missing_counter in this case.
+ *
+ * <p>- Get Bigtable zone and cluster information from response trailer and record in tracer.
  *
  * <p>This class is considered an internal implementation detail and not meant to be used by
  * applications.
@@ -49,7 +53,7 @@ public BigtableTracerUnaryCallable(@Nonnull UnaryCallable<RequestT, ResponseT> i
 
   @Override
   public ApiFuture futureCall(RequestT request, ApiCallContext context) {
-    // this should always be true
+    // tracer should always be an instance of BigtableTracer
     if (context.getTracer() instanceof BigtableTracer) {
       final GrpcResponseMetadata responseMetadata = new GrpcResponseMetadata();
       final ApiCallContext contextWithResponseMetadata = responseMetadata.addHandlers(context);