For complex UI, Flutter developers can use the ________ method to cache and reuse heavy widgets.

For complex UI in Flutter, developers can use the InheritedWidget method to cache and reuse heavy widgets. InheritedWidget is a widget that propagates information down the widget tree, efficiently rebuilding only the widgets that depend on the changed data. This can significantly improve performance by avoiding the recreation of the entire UI hierarchy and reusing existing widgets, especially when dealing with complex UI structures and data that doesn't change frequently.