isns_pdu_hdr_s
struct isns_pdu_hdr_s hdr;
if (bavail < (int64_t)sizeof(struct isns_pdu_hdr_s))
read_buf[0].iov_len = sizeof(struct isns_pdu_hdr_s);
bavail -= sizeof(struct isns_pdu_hdr_s);
more = (bavail > (int64_t)sizeof(struct isns_pdu_hdr_s)) ? 1 : 0;