Re: [PATCH v2 0/5] MR6490: winsock: Avoid short writes on nonblocking sockets.

[Jinoh Kang (＠iamahuman)]

Now that we have a flag for indicating system asyncs, I suppose we should also disable `set_fd_signaled()` for these asyncs. Might be trivial, but otherwise this subtle deviation of behavior from Windows has no FIXME and thus harder to debug.