Swift 不同版本获取keyWindow的方式

var window:UIWindow?
if #available(iOS 13, *) {
    if #available(iOS 15, *) {
        window = UIApplication.shared.connectedScenes
                    .map({ $0 as? UIWindowScene })
                    .compactMap({ $0 })
                    .first?.windows.first
    }else{
        window = UIApplication.shared.windows.first
    }
}else{
   window = UIApplication.shared.keyWindow
}