I thought iOS 11 was supposed to bring, at long last, native support for animated gifs? But I tried this, and I didn't see any animation:

```
let im = UIImage(named:"wireframe.gif")!
let iv = UIImageView(image:im)
iv.animationImages = [im] // didn't help
iv.frame.origin = CGPoint(0,100)
iv.frame.size = im.size
self.view.addSubview(iv)
delay(2) {
    iv.startAnimating() // nope
}

```

How is this supposed to work?