anchor.diff:  
   -spec crc32(Z, PrevCRC, Data) -> CRC when
         Z :: zstream(),
  -      PrevCRC :: integer(),
  -      Data :: iodata(),
  -      CRC :: integer().
  +      PrevCRC :: non_neg_integer(),
  +      Data :: iodata(),
  +      CRC :: non_neg_integer().
   crc32(Z, CRC, Data) when is_reference(Z) ->
       erlang:crc32(CRC, Data);
   crc32(_Z, _CRC, _Data) ->
  
positive.code:       Options :: list({exception_on_need_dict, boolean()}),
        Decompressed :: iolist() |
                        {need_dictionary,
                         Adler32 :: integer(),
                         Output :: iolist()}.
  inflate(Z, Data, Options) ->
      enqueue_input(Z, Data),
  
negative.code: 
  -spec crc32_combine(Z, CRC1, CRC2, Size2) -> CRC when
        Z :: zstream(),
        CRC :: non_neg_integer(),
        CRC1 :: non_neg_integer(),
        CRC2 :: non_neg_integer(),
        Size2 :: non_neg_integer().
  crc32_combine(Z, CRC1, CRC2, Size2) when is_reference(Z) ->
      erlang:crc32_combine(CRC1, CRC2, Size2);
  crc32_combine(_Z, _CRC1, _CRC2, _Size2) ->
  