public void sendHeartBeat(object source, ElapsedEventArgs e)
        {
            //check timeout
            if (timeout > interval * 2)
            {
#if LUZEXI
                protocol.onDisconnect();
#else
                protocol.getPomeloClient().disconnect();
#endif
                stop();
                return;
            }

            TimeSpan span = DateTime.Now - lastTime;
            timeout += (int)span.TotalMilliseconds;

            //Send heart beat
            protocol.send(PackageType.PKG_HEARTBEAT);
        }