didUnmountRenderObject method
A render object previously associated with this widget has been removed from the tree. The given RenderObject will be of the same type as returned by this object's createRenderObject.
Implementation
@override
void didUnmountRenderObject(covariant RenderObject renderObject) {
KrakenController controller = (renderObject as RenderObjectWithControllerMixin).controller!;
controller.dispose();
}