Rarst\Fragment_Cache\Widget_Cache::enable PHP Метод

    public function enable()
    {
        if (is_admin()) {
            add_filter('widget_update_callback', array($this, 'widget_update_callback'));
        } else {
            add_filter('widget_display_callback', array($this, 'widget_display_callback'), 10, 3);
        }
    }