Alexander P.

I've tried shifting the check to `Lib/multiprocessing/connection.py` and it seems promising, yielding the same performance improvements as having the checks in the C code. The change to `os_read_impl` would be...

1. When using `fcntl`, an additional system call per `_recv` would be necessary. The main issue is that the code must be executed inside the `_recv` function because `fcntl` requires...

Hi @cmaloney, I wanted to check in and see if there are any additional steps I need to take for this pull request before it can be reviewed by a...