AFNetworking/AFNetworking — pull request #2187 by xuzhe (2014-07-11 05:09:14+00:00)
Title: You should cancel operation for each UIControlState separately

If you are setting UIButton's image like this:

[button setImageForState:UIControlStateNormal withURL:imageURL];
[button setImageForState:UIControlStateHighlighted withURL:highlightedImageURL];
[button setImageForState:UIControlStateSelected withURL:selectedImageURL];

The old code will cause UIButton only to download the last `UIControlStateSelected` image.