移动端通知

步骤：

1. 添加框架 UserNotifications

2. 注册远程通知

let center = UNUserNotificationCenter.current()
    center.requestAuthorization(options: [.alert, .sound, .badge]) { (granted, error) in

        // Enable or disable features based on authorization.
        if granted == true
        {
            print("Allow")
            UIApplication.shared.registerForRemoteNotifications()
        }
        else
        {
            print("Don‘t Allow")
        }
    }

3. 获取Token