RVT_SEND_RESERVE_USED
wqe->wr.send_flags |= RVT_SEND_RESERVE_USED;
wqe->wr.send_flags &= ~RVT_SEND_RESERVE_USED;
if (unlikely(flags & RVT_SEND_RESERVE_USED)) {
!(flags & RVT_SEND_RESERVE_USED) &&