public static function widget($config = [])
    {
        ob_start();
        ob_implicit_flush(false);
        try {
            /* @var $widget Widget */
            $config['class'] = get_called_class();
            $widget = Reaction::create($config);
            $out = '';
            if ($widget->beforeRun()) {
                $result = $widget->run();
                $out = $widget->afterRun($result);
            }
        } catch (\Exception $e) {
            // close the output buffer opened above if it has not been closed already
            if (ob_get_level() > 0) {
                ob_end_clean();
            }
            throw $e;
        }

        return ob_get_clean() . $out;
    }