/**
  * @inheritdoc
  */
 protected function getIdentifier(ServerRequestInterface $request)
 {
     /** @var \bitExpert\Pathfinder\RoutingResult $routingResult */
     $routingResult = parent::getIdentifier($request);
     if (!$routingResult || $routingResult->failed()) {
         return null;
     }
     return $routingResult->getRoute()->getTarget();
 }