Yes, make it configurable... the last thing we want is someone reporting an issue because their actor system sometimes takes a little long to shut down (maybe due to GC pause) and then when Play restarts, it can't come back up because the old system is still listening on the remote port that the new one needs.  In fact, let's make it so by default, there's no timeout, but if a timeout is specified, it will wait for that timeout. That way, by default it does the right thing, but people that are doing bad things in Actors and taking longer to shutdown have a work around that might work.