uv__threadpool_cleanup non-op on Windows? #2980
Description
In Node.js, it looks like we've had a long standing bug when running threadpool jobs. See nodejs/node#35021 for discussion. Calling uv_library_shutdown() resolves the problem on non-Windows systems by ensuring that threadpool jobs are shutdown properly. However, I notice that uv__threadpool_cleanup() is currently a non-op on _WIN32 and it's not entirely clear why.
Removing the #ifndef _WIN guards in uv__threadpool_cleanup() fixes the bug for me locally (Windows 10, VS19). I can open a PR but before I do I wanted to see if there was a specific reason the function was a made a non-op.