Is there any real alternative to celluloid/event machine? I've seen enough of EM's implementation to be skittish using it. Ruby's async story is in a dire state

Is there any real alternative to celluloid/event machine? I've seen enough of EM's implementation to be skittish using it. Ruby's async story is in a dire state if people are seriously using Timeout today, and it doesn't look like you could plausibly write an alternative AVOIDING event machine. Thoughts?