@Override
 public String toString() {
   String channelId = "TCP channel: ";
   if (null != channel) {
     channelId += channel.toString();
   } else {
     channelId += "0";
   }
   String sender = "Netty " + channelId;
   return sender;
 }
 @Override
 public String toString() {
   return channel.toString();
 }