src/vs/base/browser/ui/tree/indexTreeModel.ts/IndexTreeModel/_setListNodeCollapseState
class IndexTreeModel:	private _setListNodeCollapseState(node: IIndexTreeNode<T, TFilterData>, listIndex: number, revealed: boolean, update: CollapseStateUpdate): boolean {
		const result = this._setNodeCollapseState(node, update, false);

		if (!revealed || !node.visible || !result) {
			return result;
		}

		const previousRenderNodeCount = node.renderNodeCount;
		const toInsert = this.updateNodeAfterCollapseChange(node);
		const deleteCount = previousRenderNodeCount - (listIndex === -1 ? 0 : 1);
		this.list.splice(listIndex + 1, deleteCount, toInsert.slice(1));

		return result;
	}