code: @Override
    public void stop() {
      stopped_ = true;
  
      // Stop queuing connect attempts asap
      stopListening();
  
      if (acceptThread != null) {
        acceptThread.wakeupSelector();
      }
      if (selectorThreads != null) {
        for (SelectorThread thread : selectorThreads) {
          if (thread != null)
            thread.wakeupSelector();
        }
      }
    }
docs: Stop serving and shut everything down.