public function handle(ServerRequestInterface $request): ResponseInterface
    {
        $msg = "This is the default request handler. This means no middleware produced a response before hitting it.";

        $contents = json_encode([
            'type' => MiddlewareStackExhaustedException::class,
            'message' => $msg,
        ]);

        $response = $this->factory
            ->createResponse(404)
            ->withHeader('Content-type', 'application/json');

        $response->getBody()->write($contents);

        return $response;
    }