Allow setting message timestamp

[GeorgeGkinis]

Proposed change

Allow setting message timestamp when pushing to a jetstream.

Use case

From my understanding so far, setting the timestamp of a message being pushed to a jetstream is not currently possible and the message gets its timestamp based on the receive time.

I would like to be able to set the timestamp when pushing to a jetstream, so I could upload historical event data (i.e. from csv using benthos), setting the timestamp based on the original event timestamp and then use replay policy: original.

If I do this now, then replaying happens in the ingestion speed when pushing to the jetstream, not the original speed.

It would be even more awesome if the messages still get ordered in the jetstream based on their timestamp, even if they are pushed out-of-order.

This is possible with influxdb (which is a DB and not a message distributor like nats.)

Contribution

Yes, if qualified.

[kfollesdal]

This would also be nice feature to have if you make your own "tired storage"

[Zetanova]

I tried this now over the header Nats-Time-Stamp but with bad results at least on nats 2.9.20

The server persist the header but still takes its own received timestamp
and the c# NATS.Client 1.1.4 does silently throws an parse exception on msg.Time.

I thin the current only workaround is use a custom header for the timestamp.

[derekcollison]

This is not supported at this time but is being considered.