dispose method
void
dispose()
Unmounts the tree so every State disposes, then releases the pipeline.
Implementation
void dispose() {
// The childless adapter only marks the root dirty; the buildScope is
// what actually swaps the child out and deactivates the subtree, and
// finalizeTree is what unmounts it. Without the drain, nothing ever
// unmounted and a resident guest leaked one whole tree per render.
RenderObjectToWidgetAdapter<RenderBox>(container: boundary)
.attachToRenderTree(_buildOwner, _element);
_buildOwner.buildScope(_element);
_buildOwner.finalizeTree();
_pipelineOwner.rootNode = null;
_renderView.child = null;
boundary.dispose();
_renderView.dispose();
_pipelineOwner.dispose();
_buildOwner.focusManager.dispose();
}