code: public synchronized void shutdown() {
      getLogger().debug(getName() + " received shutdown request");
  
      // mark this as no longer running
      active = false;
  
      if (rThread != null) {
        rThread.interrupt();
        rThread = null;
      }
      if (advertiseViaMulticastDNS) {
          zeroConf.unadvertise();
      }
  
      doShutdown();
    }
docs: Called when the receiver should be stopped. Closes the
  server socket and all of the open sockets.