algorithm.
    *   Add `unicode_encode`, `unicode_decode`, `unicode_decode_with_offsets`,
        `unicode_split`, `unicode_split_with_offset`, and `unicode_transcode`
        ops. Amongst other things, this Op adds the ability to encode, decode,
        and transcode a variety of input text encoding formats into the main
        Unicode encodings (UTF-8, UTF-16-BE, UTF-32-BE)