我正在制作一个具有在给定时间段（例如，上午8点至晚上10点）之间每30分钟发送一条消息的功能的应用。现在，我有了用于请求许可并定期发送通知的代码，但是我无法弄清楚如何在特定时间段内包含这些通知。

let center = UNUserNotificationCenter.current()

    let content = UnmutableNotificationContent()
    content.title = "Content title"
    content.body = "My content body."
    content.categoryIdentifier = "alarm"
    content.userInfo = ["customData": "fizzbuzz"]
    content.sound = UNNotificationsound.default

    let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 1,800,repeats: true)

   let request = UNNotificationRequest(identifier: UUID().uuidString,content: content,trigger: trigger)
    center.add(request)

谢谢