How to cancel downloading with the specific url

[c3522541]

Let's say I am downloading "http://a.myself.com/1.jpg", "http://a.myself.com/2.jpg", "http://a.myself.com/3.jpg" I called loadImage() for all three. At this moment, they are not done with downloading bug still in the queue. Is there any way to cancel downloading "http://a.myself.com/2.jpg"?
ImagePipeline.shared.invalidate() stops everything. I am looking for something like ImagePipeline.shared.invalidate(url: "http://a.myself.com/2.jpg")
Thanks.