code: public static Promise<Void> createDirectory(Executor executor, Path dir, @Nullable FileAttribute<?>[] attrs) {
  		return ofBlockingRunnable(executor, () -> {
  			try {
  				Files.createDirectory(dir, attrs == null ? new FileAttribute<?>[0] : attrs);
  			} catch (IOException e) {
  				throw new UncheckedException(e);
  			}
  		});
  	}
docs: Creates a new directory.
  
  @param executor executor for running tasks in other thread
  @param dir      the directory to create
  @param attrs    an optional list of file attributes to set atomically when creating the directory