src/vs/workbench/api/common/extHostTreeViews.ts/ExtHostTreeView/clear
class ExtHostTreeView:	private clear(element: T): void {
		const node = this.nodes.get(element);
		if (node) {
			if (node.children) {
				for (const child of node.children) {
					const childElement = this.elements.get(child.item.handle);
					if (childElement) {
						this.clear(childElement);
					}
				}
			}
			this.nodes.delete(element);
			this.elements.delete(node.item.handle);
			node.dispose();
		}
	}