void receiveContents(unsigned char * data, size_t len) override

    void receiveContents(std::string_view data) override

        *curMember->fileSize += len;
        (*hashSink)(data, len);

        *curMember->fileSize += data.size();
        (*hashSink)(data);

            curMember->contents->append((char *) data, len);

            curMember->contents->append(data);