Background Fetch / Swift

import  UserNotifications


func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

    UIApplication.shared.setMinimumBackgroundFetchInterval(UIApplication.backgroundFetchIntervalMinimum)
    if #available(iOS 10.0 , *){ //10이후에만 작동하므로.
        UNUserNotificationCenter.current().requestAuthorization(options: .badge) { (granted, error) in
            if error != nil {
                // success!
            }
        }
    }
    
    return true
}

func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
    
    print("haha 실행됨.")
    UIApplication.shared.applicationIconBadgeNumber = 20
   //completionHandler(.newData)
   //completionHandler(.noData)
}