src/vs/base/browser/ui/tree/asyncDataTree.ts/AsyncDataTree/_onDidChangeCollapseState
class AsyncDataTree:	private _onDidChangeCollapseState({ node, deep }: ICollapseStateChangeEvent<IAsyncDataTreeNode<TInput, T> | null, any>): void {
		if (node.element === null) {
			return;
		}

		if (!node.collapsed && node.element.stale) {
			if (deep) {
				this.collapse(node.element.element as T);
			} else {
				this.refreshAndRenderNode(node.element, false)
					.catch(onUnexpectedError);
			}
		}
	}