Fixes#28769
Use case for this is if you have a sequence of elements that has been
partitioned across multiple streams, and you want to merge them back
together in order. It will typically be used in combination with
`zipWithIndex` to define the index for the sequence, followed by a
`Partition`, followed by the processing of different substreams with
different flows (each flow emitting exactly one output for each input),
and then merging with this stage, using the index from `zipWithIndex`.
A more concrete use case is if you're consuming messages from a message
broker, and you have a flow that you wish to apply to some messages, but
not others, you can partition the message stream according to which
should be processed by the flow and which should bypass it, and then
bring the elements back together acknowledgement. If an ordinary merge
was used rather than this, the messages that bypass the processing flow
would likely overtake the messages going through the processing flow,
and the result would be out of order offset acknowledgement which would
lead to dropping messages on failure.
I've included a minimal version of the above example in the documentation.
* register ActorSystem reference under ActorFactoryRef interface name
* reformat code
* add OSGi headers for akka-protobuf-v3
* change private package to only include proto files
* Remove 'dry run' feature #29199
No longer essential because release steps can be retried/resumed more easily
nowadays
* Also remove the 'run tests' option
* using real EventSourcedBehaviorImpl
* using new inmem journal (PersistenceTestKit)
* advantages compared to a "fake" driver
* no difference in implementation details from real thing
* no limitations
* less maintance
* added internal messsages to EventSourcedBehaviorImpl to be able to grab state
and persistenceId
* GetState as InternalProtocol instead of Signal so that it is stashed
* serialization checks, using SerializationTestKit
* better testKitGuardian naming to allow multiple PersistenceTestKit
* support testing of restart
* support failure testing by using PersistenceTestKit
* update doc sample
* apidoc, reference docs, and javadsl
* Add scalafix plugin for jdk 9.
* Add command alias sortImports.
* Excludes some sources from SortImports.
* Update SortImports to 0.4.0
* Sort imports with `sortImports` command.
