File file = newDir("some-dir");

    assertThat(Files.fileTraverser().breadthFirst(rootDir)).containsExactly(rootDir, file);
  }

  public void testFileTraverser_multipleFilesAndDirectories() throws Exception {
    File fileA = newFile("file-a");
    File fileB = newFile("file-b");
    File dir1 = newDir("dir-1");
    File dir2 = newDir("dir-2");

	f, err := newFile(path)
	if err != nil {
		return fmt.Errorf("unable to create new file at %v: %w", path, err)
	}

	w.f = f

	return nil
}

// NewDir creates a new concurrency safe Writer which performs log rotation.
func NewDir(opts Options) (io.WriteCloser, error) {
	if err := os.MkdirAll(opts.Directory, os.ModePerm); err != nil {