618   msghdr msg_hdr = {};  in Send()  local
620   msg_hdr.msg_iov = &iov;  in Send()
621   msg_hdr.msg_iovlen = 1;  in Send()
630     msg_hdr.msg_control = control_buf;  in Send()
631     msg_hdr.msg_controllen = control_buf_len;  // used by CMSG_FIRSTHDR  in Send()
632     struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg_hdr);  in Send()
641   return SendMsgAllPosix(&msg_hdr);  in Send()
649   msghdr msg_hdr = {};  in Receive()  local
651   msg_hdr.msg_iov = &iov;  in Receive()
652   msg_hdr.msg_iovlen = 1;  in Receive()
656     msg_hdr.msg_control = control_buf;  in Receive()
657     msg_hdr.msg_controllen =  in Receive()
659     PERFETTO_CHECK(msg_hdr.msg_controllen <= sizeof(control_buf));  in Receive()
661   const ssize_t sz = PERFETTO_EINTR(recvmsg(*fd_, &msg_hdr, 0));  in Receive()
671     for (cmsghdr* cmsg = CMSG_FIRSTHDR(&msg_hdr); cmsg;  in Receive()
672          cmsg = CMSG_NXTHDR(&msg_hdr, cmsg)) {  in Receive()
683   if (msg_hdr.msg_flags & MSG_TRUNC || msg_hdr.msg_flags & MSG_CTRUNC) {  in Receive()