- also fixed some forgotten copy-pasta between peekNode and pollNode
- also added JavaDoc to all methods, explaining which can be used from
what thread
- did not fix the JDK8 improvement of using Unsafe instead of inheriting
from AtomicReference since that inheritance is not a bad thing,
actually
- add “mailbox-requirement” key to dispatcher section
- split out mailbox section, add akka.actor.default-mailbox
- rewrite findMarker method and use it for Props.create() and getting
the required mailbox of an actor
- add ProducesMessageQueue trait for MailboxType so that requirements
can be checked before trying to create the actor for real
- verify actor as well as dispatcher requirements for message queue
before creation, even in remote-deployed case
- change MessageDispatcher constructor to take a Configurator, add that
to migration guide
