code: public static void shutdownActive(ShutdownModeAmp mode,
                                      ExitCode exitCode, 
                                      String msg,
                                      Result<String> result)
    {
      ShutdownSystem shutdown = _activeService.get();
      
      if (shutdown != null) {
        shutdown.shutdown(mode, exitCode, msg, result);
        return;
      }
      
      shutdown = getCurrent();
      
      if (shutdown != null) {
        shutdown.shutdown(mode, exitCode, msg, result);
        return;
      }
      
      msg = ShutdownSystem.class.getSimpleName() + " is not active:\n  " + msg;
      
      log.warning(msg);
      System.out.println(msg);
      
      if (result != null) {
        result.ok(msg);
      }
    }
docs: Start the server shutdown