code: private void sendMessage(AuthenticationManagerRequest req) {
      Message<AuthenticationManagerRequest> msg = new Message<AuthenticationManagerRequest>(AuthenticationManagerCommandAction.COMMAND_NAME, req);
      try {
        sender.sendMessage(msg, null);
      } catch (Exception e) {
        log.error("Failed to update authentication.", e);
      }
    }
docs: Generically send a JGroups message to the cluster.
  
  @param req