如何从 UIImageView 的扩展内部设置 KingFisher v5.0.0 中的 indicatorType?

How to set indicatorType in KingFisher v5.0.0 from inside an extension on UIImageView?

我能够做这样的事情(使用版本 4.10.1):

extension UIImageView {
    func test() {
        self.kf.indicatorType = .activity
    }
}

现在版本 5.0.0 不再可能出现以下错误:

Cannot assign to property: 'self' is immutable

我仍然可以从分机外正常设置它。有没有办法从 UIImageView 扩展中设置 indictorType?

extension UIImageView {
 func setImages(url:String){
    let activityInd = UIActivityIndicatorView()
    activityInd.center = CGPoint(x: self.frame.size.width  / 2,
                                 y: self.frame.size.height / 2)
    activityInd.color = UIColor.red
    self.addSubview(activityInd)
    activityInd.startAnimating()
    self.kf.setImage(with: URL(string: url), placeholder: #imageLiteral(resourceName: "user-icn"), options: nil, progressBlock: nil) { (img, err, cache, url) in
        activityInd.stopAnimating()
    }
}

}

在库GitHub repository的这个issue中,原来kf变量现在引用了Kingfisher中出于性能考虑的结构,所以我们处理它需要为它创建一个副本,如下所示:

extension UIImageView {
    func test() {
        var kf = self.kf
        kf.indicatorType = .activity
    }
}