*
   * <p>Example: {@code Files.fileTraverser().depthFirstPreOrder(new File("/"))} may return files
   * with the following paths: {@code ["/", "/etc", "/etc/config.txt", "/etc/fonts", "/home",
   * "/home/alice", ...]}
   *
   * @since 23.5
   */
  public static Traverser<File> fileTraverser() {
    return Traverser.forTree(FILE_TREE);
  }

  private static final SuccessorsFunction<File> FILE_TREE =