SEND_LEN
char buf[SEND_LEN * MAX_FRAGS];
vec[i].iov_len = SEND_LEN;
EXPECT_EQ(sendmsg(self->fd, &msg, 0), SEND_LEN * frags);
EXPECT_EQ(recv(self->cfd, buf, SEND_LEN * frags, MSG_WAITALL),
SEND_LEN * frags);
EXPECT_EQ(memcmp(buf + SEND_LEN * i,
test_str, SEND_LEN), 0);