public function issueCallback()
    {
        $instance = $this->getCallbackClassInstance();

        // call the controller
        call_user_func_array([
            $instance,
            $this->getAction() . 'Action'
        ], $this->getParams());

        $response = $instance->app()->httpResponse();
        if ($response) {
            $response->send();
        }
    }