I've a subclass of UIPageControl, and I'd like to observe the changes in [`currentPage`](https://developer.apple.com/documentation/uikit/uipagecontrol/1621234-currentpage).

Unfortunately, my `currentPage`'s `didSet` isn't called when currentPage changes from taps on MyPageControl.

```
class MyPageControl: UIPageControl {
    override var currentPage: Int {
        didSet {
            // not called when `currentPage` is changed from a tap
            updateSomething(for: currentPage)
        }
    }
}

```

And the change can't be observed using KVO either:

```
class MyPageControl: UIPageControl {
    var observation: NSKeyValueObservation?
    override func awakeFromNib() {
        super.awakeFromNib()
        observation = observe(\.currentPage) { (_, _) in
            // not called when `currentPage` is changed from a tap
            updateSomething(for: self.currentPage)
        }
    }
}

```