actually, you can just pass `padding` in without changing it, because "boxed" struts can be an array OR an instance of that struct.  In other words, this could be

```ruby
Teacup.handler UIButton, :titlePadding { |target, padding|
  target.setTitleEdgeInsets(padding)  # padding can be a UIEdgeInset or an array of four numbers
}
```