Just for context, the reason for using a custom wait function (cond_wait_timeout) rather than the more idiomatic asyncio.wait_for(cond.wait(), timeout) is that the combination introduces another subtle, but nasty locking inconsistency (see https://groups.google.com/forum/#!topic/python-tulip/eSm7rZAe9LM ). Should probably open a ticket for that issue too.