anchor.diff:  -spec crc32(Z, Data) -> CRC when
         Z :: zstream(),
         Data :: iodata(),
  -      CRC :: integer().
  +      CRC :: non_neg_integer().
   crc32(Z, Data) when is_reference(Z) ->
       erlang:crc32(Data);
   crc32(_Z, _Data) ->
  
positive.code: -spec deflateSetDictionary(Z, Dictionary) -> Adler32 when
        Z :: zstream(),
        Dictionary :: iodata(),
        Adler32 :: integer().
  deflateSetDictionary(Z, Dictionary) ->
      deflateSetDictionary_nif(Z, Dictionary).
  deflateSetDictionary_nif(_Z, _Dictionary) ->
  
negative.code: 
  -spec crc32(Z, PrevCRC, Data) -> CRC when
        Z :: zstream(),
        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) ->
  