File dir2 = newFile("dir-1/dir-2");

    assertThat(Files.fileTraverser().breadthFirst(rootDir))
        .containsExactly(rootDir, fileA, fileB, dir1, dir2);
  }

  @CanIgnoreReturnValue
  private File newDir(String name) {
    File file = new File(rootDir, name);
    file.mkdir();
    return file;
  }

  @CanIgnoreReturnValue
  private File newFile(String name) throws IOException {

    private final ThreadLocal<File> fileThreadLocal = new ThreadLocal<>();

    protected File createFile() throws IOException {
      File file = File.createTempFile("SinkSourceFile", "txt");
      fileThreadLocal.set(file);
      return file;
    }

    protected File getFile() {
      return fileThreadLocal.get();
    }

  @CanIgnoreReturnValue
  private boolean delete(File file) {
    if (file.isDirectory()) {
      File[] files = file.listFiles();
      if (files != null) {
        for (File f : files) {
          if (!delete(f)) {
            return false;
          }
        }
      }
    }

    if (!file.delete()) {
      logger.log(Level.WARNING, "couldn't delete file: {0}", new Object[] {file});
      return false;

   * used for Web Video Text Tracks (WebVTT) files, used with the HTML5 track element.
   *
   * @since 20.0
   */
  public static final MediaType VTT_UTF_8 = createConstantUtf8(TEXT_TYPE, "vtt");

  /* image types */
  /**
   * <a href="https://en.wikipedia.org/wiki/BMP_file_format">Bitmap file format</a> ({@code bmp}
   * files).
   *
   * @since 13.0
   */

 * A callback to be used with the streaming {@code readLines} methods.
 *
 * <p>{@link #processLine} will be called for each line that is read, and should return {@code
 * false} when you want to stop processing.
 *
 * @author Miles Barr
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public interface LineProcessor<T extends @Nullable Object> {

  /**
   * This method will be called once for each line.

 * the License.
 */

/**
 * Utility methods and classes for I/O; for example input streams, output streams, readers, writers,
 * and files.
 *
 * <p>At the core of this package are the Source/Sink types: {@link ByteSource ByteSource}, {@link
 * CharSource CharSource}, {@link ByteSink ByteSink} and {@link CharSink CharSink}. They are

     * including in MapRetrievalCache, so I'm not sure why this one is different. I did at least
     * confirm that my change to MapIteratorCache fixes the TSAN error in the (larger) test it was
     * originally reported in.
     */
    for (Future<?> future : futures.build()) {
      future.get();
    }
    executor.shutdown();
  }

     * including in MapRetrievalCache, so I'm not sure why this one is different. I did at least
     * confirm that my change to MapIteratorCache fixes the TSAN error in the (larger) test it was
     * originally reported in.
     */
    for (Future<?> future : futures.build()) {
      future.get();
    }
    executor.shutdown();
  }

      ListenableFuture<? extends V>... futures) {
    ListenableFuture<List<@Nullable V>> nullable =
        new ListFuture<V>(ImmutableList.copyOf(futures), true);
    // allAsList ensures that it fills the output list with V instances.
    @SuppressWarnings("nullness")
    ListenableFuture<List<V>> nonNull = nullable;
    return nonNull;
  }

  /**

      assertTrue(file.exists());
      assertThat(file.getName()).contains("FileBackedOutputStream");
      if (!isAndroid() && !isWindows()) {
        PosixFileAttributes attributes =
            java.nio.file.Files.getFileAttributeView(file.toPath(), PosixFileAttributeView.class)
                .readAttributes();
        assertThat(attributes.permissions()).containsExactly(OWNER_READ, OWNER_WRITE);
      }
    }
    out.close();