src/vs/base/browser/ui/tree/dataTree.ts/DataTree/constructor
class DataTree:	constructor(
		private user: string,
		container: HTMLElement,
		delegate: IListVirtualDelegate<T>,
		renderers: ITreeRenderer<T, TFilterData, any>[],
		private dataSource: IDataSource<TInput, T>,
		options: IDataTreeOptions<T, TFilterData> = {}
	) {
		super(user, container, delegate, renderers, options as IDataTreeOptions<T | null, TFilterData>);
		this.identityProvider = options.identityProvider;
	}