How to add a local backup directory when using blob storage

[fschon]

When creating a blog storage, how can I configure a local backup directory?

	public EmbeddedStorageManager startStorage(Object root, AFileSystem aFileSystem) {
		ADirectory aDirectory = aFileSystem.ensureDirectoryPath(s3Bucket);
		ADirectory folder = aDirectory.ensureDirectory(directory);
		var embeddedStorageManager = EmbeddedStorage.start(root, folder);
		return embeddedStorageManager;
	}