首先__kindof：规定参数为UITableViewCell(举例)这个类或者其子类。比如说一个NSArray<UIView *>*,如果不加__kindof，这个数组只能有UIView,即便是其子类也不行。而加了的话，传入UIImageView或者UIButton之类的不会有问题。
而__typeof会返回对应的类型。
if marked as __kindof, that the compiler won't complain if you try to access ones of its elements, and store the result in a variable who's type is UIView or one of its subclasses.
参考链接：
1.https://happyteamlabs.com/blog/how-to-use-__kindof-in-objective-c/
2.https://stackoverflow.com/questions/31399208/ios-kindof-nsarray/33013094#33013094
3.http://www.jianshu.com/p/3f73e696dd4d
4.http://www.itstrike.cn/Question/b06eefce-1d13-4ace-a8db-a93e36fe2634.html
5.https://www.infoq.com/articles/whats-new-ios9-swift-objc