keepAliveWithoutCalls probably not useful for gRPC read journal

[johanandren]

We set it to avoid some shutdown but it probably does not do what we expect it to.
https://github.com/akka/akka-projection/blob/main/akka-projection-grpc/src/main/scala/akka/projection/grpc/consumer/scaladsl/GrpcReadJournal.scala#L143

From the Netty docs, the Netty channels are closed after 30 minutes of idle time, to save resources, idle time for gRPC means no RPC calls, but for the read journal we constantly have a running events by slice stream call, so it should never hit that timeout.

Could ofc be that it doesn't work as advertised, so needs to be verified that removing the config doesn't break anything.

[patriknw]

Thanks, and for reference the original reason for adding it was a "Connection reset by peer" and

[2022-06-03 14:02:40,005] [DEBUG] [akka.actor.RepointableActorRef] [akka://[email protected]:2551] [] [ShoppingCartService-akka.actor.default-dispatcher-28] - Aborting tcp connection to /127.0.0.1:55228 because of upstream failure: akka.http.impl.engine.HttpIdleTimeoutException: HTTP idle-timeout encountered on connection to [/127.0.0.1:55228], no bytes passed in the last 60 seconds. This is configurable by akka.http.[server|client].idle-timeout.