A function that wraps all of the children that are transitioning out, and the child that's transitioning in, with a widget that lays all of them out. This is called every time this widget is built. The function must not return null.
The default is AnimatedSwitcher.defaultLayoutBuilder.
- AnimatedSwitcherLayoutBuilder for more information about how a layout builder should function.
final AnimatedSwitcherLayoutBuilder layoutBuilder