See the comment on Discourse here: https://discuss.python.org/t/feeding-data-generated-via-asyncio-into-a-synchronous-main-loop/5436/28 (and the thread leading up to this comment).

In the thread, @njs states that if the user hits Ctrl-C while the asyncio event loop is running, it's possible for internal asyncio data structures to end up in an inconsistent state. If that's the case, then this would make asyncio-based code unreliable in real-world use.

I don't have a way to reproduce this - from the Discourse thread, I had assumed that ctrl-C was safe to use on an asyncio-based program, but was told otherwise, and I can't find anything definitive either way.

At a minimum, the asyncio documentation should confirm that it is exception-safe (specifically against Ctrl-C, but in general I'd assume that asyncio is safe in the face of uncaught exceptions in user-written async code).

Duplicate for #39622