src/vs/workbench/api/browser/mainThreadFileSystem.ts/MainThreadFileSystem/$readdir
class MainThreadFileSystem:	$readdir(uri: UriComponents): Promise<[string, FileType][]> {
		return this._fileService.resolve(URI.revive(uri), { resolveMetadata: false }).then(stat => {
			if (!stat.isDirectory) {
				const err = new Error(stat.name);
				err.name = FileSystemProviderErrorCode.FileNotADirectory;
				throw err;
			}
			return !stat.children ? [] : stat.children.map(child => [child.name, MainThreadFileSystem._asFileType(child)] as [string, FileType]);
		}).catch(MainThreadFileSystem._handleError);
	}