int io_trywritetimeout(int64 fd,const char* buf,int64 len);
io_trywritetimeout is identical to io_trywrite, with the following exception: if
- io_trywrite returns -1 (the descriptor is not ready for writing), and
- the descriptor has a timeout, and
- the write attempt was after the descriptor's timeout,
then io_trywritetimeout instead returns -2, with errno set to ETIMEDOUT.
io_nonblock(3), io_waitwrite(3), io_trywrite(3)