xpc_notify_mq_msghdr_uv
struct xpc_notify_mq_msghdr_uv hdr;
msg_size = sizeof(struct xpc_notify_mq_msghdr_uv) + payload_size;
sizeof(struct xpc_notify_mq_msghdr_uv));
if (sizeof(struct xpc_notify_mq_msghdr_uv) > XPC_MSG_HDR_MAX_SIZE) {