Make send_socket alert the async immediately if poll() call detects that
there are incoming data in the socket, bypassing the wineserver's main
polling loop.

For sock_transmit, we always mark the async as pending and set the IOSB
(unless async allocation has failed).
Signed-off-by: Jinoh Kang <jinoh.kang.kr@gmail.com>
Signed-off-by: Zebediah Figura <zfigura@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>