buildParent method
- ScrollPhysics? ancestor
If parent is null then return ancestor, otherwise recursively build a
ScrollPhysics that has ancestor as its parent.
This method is typically used to define applyTo methods like:
class MyScrollPhysics extends ScrollPhysics {
  const MyScrollPhysics({ super.parent });
  @override
  MyScrollPhysics applyTo(ScrollPhysics? ancestor) {
    return MyScrollPhysics(parent: buildParent(ancestor));
  }
  // ...
}
Implementation
@protected
ScrollPhysics? buildParent(ScrollPhysics? ancestor) => parent?.applyTo(ancestor) ?? ancestor;