code: public synchronized void shutdown() {
      // mark this as no longer running
      active = false;
  
      // close the socket
      try {
        if (socketNode != null) {
          socketNode.close();
          socketNode = null;
        }
      } catch (Exception e) {
        getLogger().info("Excpetion closing socket", e);
        // ignore for now
      }
  
      // stop the connector
      if (connector != null) {
        connector.interrupted = true;
        connector = null;  // allow gc
      }
      if (advertiseViaMulticastDNS) {
          zeroConf.unadvertise();
      }
    }
docs: Called when the receiver should be stopped. Closes the socket