anchor.diff:      throw "to be implemented";
     }
   
  -}
  +}
positive.code:     List<int> header = encodeUtf8(PackedTypes.getTypeString(type)
          + " ${contentData.length}\u0000");
  
      Uint8List fullContent = 
          new Uint8List(header.length + contentData.length);
  
      fullContent.setAll(0, header);
  
negative.code:         maskedByte = (byte & 0x7f);
          shiftedByte = (maskedByte << currentShift);
          result += shiftedByte;
          currentShift += 7;
        }
  
        stream.offset = offset;
        return result;
      }
  
      DeltaDataStream stream = new DeltaDataStream(deltaData, 0);
  