async function listFileRecursive(dir, files) {
	for (const child of await fsOperation(dir).lsDir()) {
		const fileUrl = Url.join(dir, child.name);
		if (child.isDirectory) {
			await listFileRecursive(fileUrl, files);
		} else {
			files.push(fileUrl);
		}
	}
}
@param {string} dir
@param {Array<string>} files