Informs the delegate that the given layout manager has invalidated layout information (not glyph information).
- iOS 7.0+
- macOS 10.0+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
The layout manager that invalidated layout.
This method is invoked only when layout was complete and then became invalidated for some reason. Delegates can use this information to show an indicator of background layout or to enable a button that forces immediate layout of text.