src/vs/platform/files/browser/indexedDBFileSystemProvider.ts/IndexedDBFileSystemProvider/getFiletree
class IndexedDBFileSystemProvider:	private getFiletree(): Promise<IndexedDBFileSystemNode> {
		if (!this.cachedFiletree) {
			this.cachedFiletree = (async () => {
				const rootNode = new IndexedDBFileSystemNode({
					children: new Map(),
					path: '',
					type: FileType.Directory
				});
				const result = await this.indexedDB.runInTransaction(this.store, 'readonly', objectStore => objectStore.getAllKeys());
				const keys = result.map(key => key.toString());
				keys.forEach(key => rootNode.add(key, { type: 'file' }));
				return rootNode;
			})();
		}
		return this.cachedFiletree;
	}