> I'm not convinced that the PR is worth it. 3% is not interesting on a micro benchmark.

I found a small issue in the PR (left a comment in the PR).

I think using a tuple is still a good idea (even if the speedup is tiny) because logically, both attributes on that threading.local() object are always set and read at the same time.  Essentially, it's a pair of (loop, pid), so using a tuple here makes the code easier to reason about.