* Improve error message when pushing unpulled outlet
If an outlet is pushed to before it has been pulled, the error message
is "Cannot push twice", which makes sense if after receiving a pull, you
push twice, but makes no sense if you never received a pull in the first
place. This improves the error message to avoid confusion.
* Reword message slightly
The test has been failing infrequently as when we get to the final
barrier (restarted-fifth-removed) the whole test withIn of 40s
has been reached so the last barrier times out right away.
Trying to remove the Thread.sleep and rely on a larger timeout for the
whole test as well as the default barrier timeout of 30s.
* DaemonMsgCreate is not a system message. We send it over the control
stream because remote deployment process depends on message ordering
for DaemonMsgCreate and Watch messages. That is all good.
* We also send DaemonMsgCreate over the ordinary message stream (all
outbound lanes) so that the first ordinary message that is sent to
the ref does not arrive before the actor is created. This is not needed,
since the retried resolve in the Decoder will take care of that anyway.
* Inbound lanes were not covered, but not needed.
* Then the deduplication of DaemonMsgCreate messages in RemoteSystemDaemon
is not needed.
* Added some more tests for these things.
* describe lanes in reference docs
* Pass HandshakeReq in all inbound lanes, #23527
The HandshakeReq message must be passed in each inbound lane to
ensure that it arrives before any application message. Otherwise there is a risk
that an application message arrives in the InboundHandshake stage before the
handshake is completed and then it would be dropped.
* mima
* Apply [Boy scout rule](https://github.com/akka/akka/blob/master/CONTRIBUTING.md#additional-guidelines)
* [Bug#23329] PersistentFSM: andThen callbacks are not executed when stay()
* [fixes#23329] PersistentFSM: andThen callbacks go execute when stay()
* At documentation: there is nothing said about events applied should decide to invoke andThen or not.
* At code: andThen callback can be specified whether any events/state transition applied or not.
Added call to nextState.afterTransitionDo(stateData) even if there are no eventsToPersist
* looks like the ActorSystem is shutdown when leaving
* Included in MultiNodeSpec, i.e. all multi-node tests:
akka.coordinated-shutdown.terminate-actor-system = off
akka.oordinated-shutdown.run-by-jvm-shutdown-hook = off
* This is an optimization of TcpStreamLogic to accumulating bytes in a buffer while waiting for
acknoledgment of pending write. This improves throughput for small messages (frames)
without sacrificing latency. While waiting for the ack the stage will eagerly pull
from upstream until the buffer limit is exceeded. Accumulated bytes are written
immediately when ack is received.
* Noticed 20x throughput improvement with Artery MaxThroughputSpec thanks to this buffer
when working on the Artery TCP implementation. The small message (100 bytes) benchmark
improved from 30k msg/s to 600k msg/s.
