This commit refactors the Actor implementation to use the new Mailbox
interface instead of directly managing a channel. This change
significantly simplifies the actor's message processing loop and
improves separation of concerns.
The main changes include replacing the direct channel field with a
Mailbox interface, updating NewActor to create a ChannelMailbox
instance, and refactoring the process method to use the iterator
pattern provided by mailbox.Receive. The new implementation uses a
clean for-range loop over the mailbox's message iterator, eliminating
the complex select statement that previously handled both message
reception and context cancellation.
The Tell and Ask methods in actorRefImpl have been simplified to use
the mailbox's Send method, which internally handles both the caller's
context and the actor's context. This eliminates the need for complex
select statements in these methods and ensures consistent context
handling throughout the actor system.
Message draining during shutdown is now handled through the mailbox's
Drain method, providing a cleaner separation between normal message
processing and cleanup operations. The actor still properly sends
unprocessed messages to the Dead Letter Office and completes pending
promises with appropriate errors during shutdown.
In this commit, we add the actual Actor implementation. We define a
series of types and interfaces, that in concert, describe our actor. An
actor has some ID, a reference (used to send messages to it), and also a
set of defined messages that it'll accept.
An actor can be implemented using a simple function if it's stateless.
Otherwise, a struct can implement the Receive method, and handle its
internal message passing and state that way.