}
  }

  /**
   * 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();