test/zc: test short zc send
test/zc: test short zc send

Zerocopy send should hide short writes for stream sockets, test it.

Signed-off-by: Pavel Begunkov <8608d41fe50396a9dbd36e830be65ba791e26c05@gmail.com>
Link: https://lore.kernel.org/r/6ee389d6b720356ec2a8c677a34a852c761c1627.1659622771.git.8608d41fe50396a9dbd36e830be65ba791e26c05@gmail.com
Signed-off-by: Jens Axboe <cd8c6775e60d6f67a6984377324e5290df3d5358@kernel.dk>

axboe/liburing,axboe/liburing,axboe/liburing