code: public void shutDown() {
          synchronized (channels) {
              isCurrentlyShutingDown = true;
              for (final SynchronizeFXWebsocketChannel server : channels.values()) {
                  server.shutdown();
              }
              servers.clear();
              channels.clear();
              clients.clear();
              isCurrentlyShutingDown = false;
          }
      }
docs: Shuts down this servers with all its channels and disconnects all remaining clients.