private final byte[] initialBytes;

    private FileByteSinkFactory(byte @Nullable [] initialBytes) {
      this.initialBytes = initialBytes;
    }

    @Override
    public ByteSink createSink() throws IOException {
      File file = createFile();
      if (initialBytes != null) {
        FileOutputStream out = new FileOutputStream(file);
        try {
          out.write(initialBytes);

   * will append to the end of the file without truncating it.
   *
   * @since 14.0
   */
  public static ByteSink asByteSink(File file, FileWriteMode... modes) {
    return new FileByteSink(file, modes);
  }

  private static final class FileByteSink extends ByteSink {

    private final File file;
    private final ImmutableSet<FileWriteMode> modes;

   * WRITE} options.
   */
  public static ByteSink asByteSink(Path path, OpenOption... options) {
    return new PathByteSink(path, options);
  }

  @IgnoreJRERequirement // *should* be redundant with the one on MoreFiles itself
  private static final class PathByteSink extends ByteSink {

    private final Path path;
    private final OpenOption[] options;

   * StandardOpenOption#TRUNCATE_EXISTING TRUNCATE_EXISTING} and {@link StandardOpenOption#WRITE
   * WRITE} options.
   */
  public static ByteSink asByteSink(Path path, OpenOption... options) {
    return new PathByteSink(path, options);
  }

  private static final class PathByteSink extends ByteSink {

    private final Path path;
    private final OpenOption[] options;

    }
  }

  /**
   * Copies the contents of this byte source to the given {@code ByteSink}.
   *
   * @return the number of bytes copied
   * @throws IOException if an I/O error occurs while reading from this source or writing to {@code
   *     sink}
   */
  @CanIgnoreReturnValue
  public long copyTo(ByteSink sink) throws IOException {
    checkNotNull(sink);

    Closer closer = Closer.create();