* deduplicate logic for IODispatcher #24604
* introduce a resolveDispatcher helper in ActorAttributes
* mention akka.stream.materializer.blocking-io-dispatcher instead of akka.stream.blocking-io-dispatcher in scaladocs
* fix a flaky test
* cosmetic changes in the touched files
* move resolveDispather helper to the Dispatcher companion object under a new name resolve
* filter out mima warning
* fix mima excludes after the 2.5.11 release
* address review comments
* update stream-io.md with the correct dispatcher config key
* mark ActorAttributes.Dispatcher#resolve as internal API
* use the dispatche config key in ActorMaterializer
* add private[akka] to the resolve methods
Instead of renaming - deprecating and documenting
Renaming defaultInitialAttributes to defaultAttributes and adding docs
Tests passing
More work on using attributes for the attribute settings in ActorMaterializerSettings
Mark some attributes as mandatory and provide a smoother access w/o allocation for those
Another warning notice
MiMa filters
Part of the review adressed
Incorrect rebase fixed + formatting
Review feedback adressed
Formatting ...
* #22506 Mark materializer extension as @InternalApi
* #22506 Added missing annotations on internal apis in the fusing package
* #22506 Missing annotations in io package
* #22506 Add internal api annotations in impl package
* #22563 more hiding of the classes in the impl package
* #22563 Formatting fixes
* #22506 Fix private access in stream tcl tests
* these must also be included via setAttributes because
because it will create island for async (dispatcher attribute)
* better actor name of GraphStageIsland, we need it in tests for
lookup of the actor
* this unlocks OutputStreamSourceSpec and InputStreamSinkSpec
* Fixed island application
* Switched to explicit island boundaries and fixed misapplied island tags
* Added missing attributes for non-stage backed Sinks
