How to get the size of a UITableView's content view?

I don't know how much people will like this answer because I am not sure that I like it. But I managed to get something working with this.

This will work for dynamic height cells. The callback will get called a few times as the tableview figures out its contentView

class ContentSizeNotifyingTableView: UITableView {
    var contentSizeDidChange: ((CGSize) -> ())?

    override var contentSize: CGSize {
        didSet {
          self.contentSizeDidChange?(self.contentSize)
        }
    }
}