如果关闭设备电源，则推送通知不会通过UNNotificationServiceExtension

Question

我正在尝试实现UNNotificationServiceExtension，以便可以在显示推送通知之前修改其内容。它工作正常，但我注意到一种情况，即推送通知不通过UNNotificationServiceExtension。

复制步骤：

1. 关闭设备电源
2. 将推送通知发送到设备
3. 打开设备
4. 当设备连接到wifi /蜂窝网络时，推送通知就会出现

结果： 推送通知不会通过UNNotificationServiceExtension进行，UNNotificationServiceExtension会修改标题和正文的内容。仅当我在连接wifi /蜂窝网络之前启动主机应用程序时，此过程才能通过。

预期： 推送通知应始终通过UNNotificationServiceExtension。

这是预期的行为吗？不能保证推送通知总是通过UNNotificationServiceExtension吗？

这是我用于实现UNNotificationServiceExtension的代码：

class NotificationService: UNNotificationServiceExtension {

    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        guard let bestAttemptContent = bestAttemptContent else { return }

        bestAttemptContent.title = "title has been modified by extension"
        bestAttemptContent.body = "body has been modified by extension"

        contentHandler(bestAttemptContent)
    }

    override func serviceExtensionTimeWillExpire() {
        // Called just before the extension will be terminated by the system.
        // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
        if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
        contentHandler(bestAttemptContent)
        }
    }
}

和我的有效载荷：

{
  "aps": {
    "alert": {
      "body": "my body",
      "title": "my title"
    },
    "content-available": 1,
    "mutable-content": 1
  }
}