## Actor

A store of some state. Emits events and handles events.


## _QueuedMessage

A message that can be queued for delivery in a MessageDispatcher.


## _InFlightMessage

A message that queued for delivery by a MessageDispatcher.


## _StartStopActor

Start or stop an Actor.


## _CallLater

## _QuarkRuntimeLaterCaller

## _ManualLaterCaller

## MessageDispatcher

Manage a group of related Actors.

Each Actor should only be started and used by one MessageDispatcher.

Reduce accidental re-entrancy by making sure messages are run asynchronously.