code: public void terminate() {
      if (!isTerminated()) {
        for (final Stage stage : stages.values()) {
          stage.stop();
        }
  
        loggerProviderKeeper.close();
        mailboxProviderKeeper.close();
        completesProviderKeeper.close();
      }
    }
docs: Initiates the {@code World} terminate process if the process has not already been initiated.