@vibhavp @gofman - you've both worked in `server/sock.c` and the ws2_32 socket tests recently, so flagging this in case either of you has a moment to take a look. Short version: it reports a connected stream socket writable in `poll_socket()` while its send buffer still has room (`TIOCOUTQ < SO_SNDBUF`), to match Windows `select()`. Without it, an app-limited libcurl-style sender that never trips `WSAEWOULDBLOCK` sees the socket as not writable while its sends keep succeeding and waits out the poll timeout, throttling single-stream uploads to \~140 KB/s under Wine. It was floated as an RFC on wine-devel first; the root cause, the Windows-semantics-not-a-Windows-fix reasoning, and the test (a `todo_wine` flip) are all in the description. No urgency, and thanks either way. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/11272#note_144361