protected function notify($title, $message, $icon = null)
    {
        $app = __DIR__ . '/../../bin/toast.exe';

        $title   = iconv('UTF-8', 'ASCII//TRANSLIT', $title);
        $message = iconv('UTF-8', 'ASCII//TRANSLIT', $message);

        $icon = is_string($icon) ? " -p \"$icon\"" : $this->icon;
        $this->execute("$app -t \"{$title}\" -m \"{$message}\"$icon");
    }