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

    assertThat(Iterables.limit(Files.fileTraverser().breadthFirst(rootDir), 3))
        .containsExactly(rootDir, fileA, dir1);
  }

  }

  public void testFileTraverser_multipleDirectoryLayers_breadthFirstStartsWithTopLayer()
      throws Exception {
    Path fileA = newFile("file-a");
    Path dir1 = newDir("dir-1");
    newFile("dir-1/file-b");
    newFile("dir-1/dir-2");

    assertThat(Iterables.limit(MoreFiles.fileTraverser().breadthFirst(rootDir), 3))
        .containsExactly(rootDir, fileA, dir1);
  }

    return new byte[BUFFER_SIZE];
  }

  /**
   * There are three methods to implement {@link FileChannel#transferTo(long, long,
   * WritableByteChannel)}:
   *
   * <ol>
   *   <li>Use sendfile(2) or equivalent. Requires that both the input channel and the output
   *       channel have their own file descriptors. Generally this only happens when both channels

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

    assertThat(Iterables.limit(Files.fileTraverser().breadthFirst(rootDir), 3))
        .containsExactly(rootDir, fileA, dir1);
  }