/**
  * @param ServerRequestInterface $request
  * @param ResponseInterface $response
  *
  * @return ResponseInterface
  */
 public function handleNotFound(ServerRequestInterface $request, ResponseInterface $response)
 {
     if ($level = $this->shouldLog('not-found')) {
         $message = $request->getRequestTarget();
         $this->logEvent('not-found', $message, $level);
     }
     return $this->handler->handleNotFound($request, $response);
 }