vd_dring_inband_msg_t
sizeof (vd_dring_inband_msg_t) +
expected_inband_size(vd_dring_inband_msg_t *msg)
vd_dring_inband_msg_t *desc_msg = (vd_dring_inband_msg_t *)msg;
desc_msg = (vd_dring_inband_msg_t *)vd->inband_task.msg;