return new ByteArrayByteSource(bytes, newOffset, (int) length);
    }

    @Override
    public String toString() {
      return "ByteSource.wrap("
          + Ascii.truncate(BaseEncoding.base16().encode(bytes, offset, length), 30, "...")
          + ")";
    }
  }

  private static final class EmptyByteSource extends ByteArrayByteSource {