public function userEnqueue($markup, array $args = [])
    {
        if (!isset($args['for_user_id'])) {
            $args['for_user_id'] = (int) get_current_user_id();
        }
        if (!$args['for_user_id']) {
            return; // Nothing to do.
        }
        $this->enqueue($markup, $args);
    }