            // check client heartbeats
            if Instant::now().duration_since(act.hb) > CLIENT_TIMEOUT {
                // heartbeat timed out
                log::error!("Websocket Client heartbeat failed, disconnecting!");

                // stop actor
                ctx.stop();
                act.monitor_address.do_send( DeRegisterGPSWebSocketClient{uuid: act.uuid} );

                // don't try to send a ping