/**
  * @return RdsQueue
  */
 protected function getInstance()
 {
     $serviceManager = ServiceManager::getServiceManager();
     try {
         $rdsQueueService = $serviceManager->get(RdsQueue::CONFIG_ID);
     } catch (ServiceNotFoundException $e) {
         $rdsQueueService = null;
     }
     if (!$rdsQueueService instanceof RdsQueue || $rdsQueueService === null) {
         $rdsQueueService = new RdsQueue([RdsQueue::OPTION_PERSISTENCE => 'default']);
         $rdsQueueService->setServiceManager($serviceManager);
     }
     return $rdsQueueService;
 }