private function generateNotFoundPlainResponse(ServerRequestInterface $request) : ResponseInterface
    {
        $response = ($this->responseFactory)()->withStatus(StatusCodeInterface::STATUS_NOT_FOUND);
        $response->getBody()
            ->write(\sprintf(
                "Encountered a 404 Error, %s doesn't exist",
                (string) $request->getUri()
            ));

        return $response;
    }