Comment 7 for bug 1848457

So, possibly the culprit is eventlet there.

Your execution seems stuck by eventlet [1].

In this case, if I understand it correctly, it's more related to a coroutine who doesn't call the send method. I'm not sure this is is related to a lock.

Can you try to move your break point there [1] and to trace the execution step by step if it's possible.

Anyway, I think my initial changes can help to improve things.

[1] https://github.com/eventlet/eventlet/blob/master/eventlet/event.py#L95