static pj_status_t tls_shutdown(pjsip_transport *transport)
{
    struct tls_transport *tls = (struct tls_transport*)transport;
    
    /* Stop keep-alive timer. */
    if (tls->ka_timer.id) {
	pjsip_endpt_cancel_timer(tls->base.endpt, &tls->ka_timer);
	tls->ka_timer.id = PJ_FALSE;
    }

    return PJ_SUCCESS;
}
static pj_status_t tls_shutdown(pjsip_transport *transport)
{
    struct tls_transport *tls = (struct tls_transport*)transport;
    
     
    if (tls->ka_timer.id) {
	pjsip_endpt_cancel_timer(tls->base.endpt, &tls->ka_timer);
	tls->ka_timer.id = PJ_FALSE;
    }

    return PJ_SUCCESS;
}