private function renderNotFound(GetResponseForExceptionEvent $event, $template, array $context = [])
    {
        try {
            $html = $this->twig->resolveTemplate($template)->render($context);
            $event->setResponse(new Response($html, Response::HTTP_NOT_FOUND));
        } catch (RuntimeError $e) {
            throw new RuntimeException('Unable to render 404 page!', null, $e);
        }
    }