Flarum\Api\JsonApiResponse::__construct PHP Method

    public function __construct(Document $document, $status = 200, array $headers = [], $encodingOptions = 15)
    {
        $headers['content-type'] = 'application/vnd.api+json';
        // The call to jsonSerialize prevents rare issues with json_encode() failing with a
        // syntax error even though Document implements the JsonSerializable interface.
        // See https://github.com/flarum/core/issues/685
        parent::__construct($document->jsonSerialize(), $status, $headers, $encodingOptions);
    }