dispose method
Called when its corresponding element disposed
Implementation
@override
@mustCallSuper
void dispose() {
_disposed = true;
super.dispose();
// Dispose scroll behavior
disposeScrollable();
// Clear all paint layers
_colorFilterLayer.layer = null;
_imageFilterLayer.layer = null;
disposeTransformLayer();
disposeOpacityLayer();
disposeIntersectionObserverLayer();
// Dispose box decoration painter.
disposePainter();
// Evict render decoration image cache.
renderStyle.backgroundImage?.image?.evict();
}