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

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

            else:
                await self._load_field(ftype, params, x.eref(msg, fname))

            self.tracker.pop()

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