Dumps/Loads message field
        :param msg:
        :param field:
        :param fvalue: explicit value for dump
        :return:

async def message_field(self, msg, field, fvalue=None):
        """
        Dumps/Loads message field
        :param msg:
        :param field:
        :param fvalue: explicit value for dump
        :return:
        """
        fname, ftype, params = field[0], field[1], field[2:]
        try:
            self.tracker.push_field(fname)
            if self.writing:
                await self._dump_message_field(self.iobj, msg, field, fvalue=fvalue)
            else:
                await self._load_message_field(self.iobj, msg, field)
            self.tracker.pop()

        except Exception as e:
            raise helpers.ArchiveException(e, tracker=self.tracker) from e