protected function getApiDocument(User $actor, array $params)
    {
        $response = $this->api->send('Flarum\Api\Controller\ShowDiscussionController', $actor, $params);
        $statusCode = $response->getStatusCode();

        if ($statusCode === 404) {
            throw new RouteNotFoundException;
        }

        return json_decode($response->getBody());
    }