您可以调用退出方法

exit(-1)

或者您可以使用 NSXPCConnection.suspend

UIControl().sendAction(#selector(NSXPCConnection.suspend),
                       to: UIApplication.shared, for: nil)

此外，Apple不建议强制终止您的应用程序.没关系，怎么做.

Besides Apple isn't recommending to force terminate your app. It doesn't matter how you do that.

检查此帖子.