code: protected function applyRoutingResult(
          ServerRequestInterface $request,
          RoutingResult $routingResult
      ) : ServerRequestInterface {
          $routingParams = $routingResult->getParams();
          $params = array_merge($request->getQueryParams(), $routingParams);
          return $request->withQueryParams($params);
      }
docs: Offers possibility to manipulate the request according to routing result.
  Returns a new {@link \Psr\Http\Message\ServerRequestInterface}.
  
  @param ServerRequestInterface $request
  @param RoutingResult $routingResult
  @return ServerRequestInterface