在通知的内容主体中显示倒计时

Question

我正在显示一条通知，要求用户在接下来的10秒钟内采取一些措施，否则它将有所作为。

我想做的是每秒更新通知的文本，以便用户知道他还有多少时间可以采取行动，例如。 Device not connected. Restarting watcher in X seconds其中X每秒更新为0。

这是我到目前为止所拥有的：

    let centre = UNUserNotificationCenter.current();
    let content = UNMutableNotificationContent();
    var i:Int = 10;

    content.title = NSString.localizedUserNotificationString(forKey: "This is the title", arguments: nil)
    content.body = NSString.localizedUserNotificationString(forKey: "Device not connected. Restarting watcher in \(i) seconds", arguments: nil)
    content.categoryIdentifier = "Category";
    content.sound = UNNotificationSound.default;

    let request = UNNotificationRequest(identifier: "FiveSecond", content: content, trigger: UNTimeIntervalNotificationTrigger(timeInterval: 1, repeats: false));

    let completeAction = UNNotificationAction.init(identifier: "Complete", title: "Complete", options: UNNotificationActionOptions())
    let categories = UNNotificationCategory.init(identifier: "Category", actions: [completeAction], intentIdentifiers: [], options: [])

    centre.setNotificationCategories([categories]);
    centre.add(request, withCompletionHandler: nil);

    let timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) {_ in
        i-=1;
    }

    DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(10)) {
        timer.invalidate();
        centre.removeDeliveredNotifications(withIdentifiers: ["FiveSecond"]);
    };
}

有可能做到吗？