Akka.Actors: schedule one-off tasks with IWithTimers

[Aaronontheweb]

Is your feature request related to a problem? Please describe.

One of the things that has made it difficult for us to consistently resolve AK1004 everywhere inside our own code-base is the use of unique timer keys. There are many cases where you do not want a unique timer key for a recurring task - the change I just made to Akka.IO is a good example of one:

akka.net/src/core/Akka/IO/TcpListener.cs

Lines 174 to 179 in eb8db42

	case SocketError.WouldBlock:
	// transient – short back‑off then retry
	saea.AcceptSocket = null;
	Context.System.Scheduler.ScheduleTellOnce(TimeSpan.FromMilliseconds(10), Self,
	new RetryAccept(saea), ActorRefs.NoSender);
	break;

If I have n socket operations that all failed, I need to reschedule each one independently - today that will require me to generate a key-per-socket if I want to use IWithTimers. If I just use the old scheduler directly instead, I no longer have that problem.

Describe the solution you'd like

It would be great if we could create a "keyless" timer for single-shot timers only for this type of task: a specific, self-describing unit of work that needs to be delayed until some point in the future. We can still cancel this unit of work when the actor shuts down (because: key is synthetic and stored internally

Describe alternatives you've considered

Just go back to using the scheduler, which is what we're doing currently, but this also requires suppressing AK1004 warnings.