Iterate (buid, valu) rows for the given universal prop

async def iterUnivRows(self, prop):
        '''
        Iterate (buid, valu) rows for the given universal prop
        '''
        penc = prop.encode()
        pref = penc + b'\x00'

        for _, pval in self.layrslab.scanByPref(pref, db=self.byuniv):
            buid = s_msgpack.un(pval)[0]

            byts = self.layrslab.get(buid + penc, db=self.bybuid)
            if byts is None:
                continue

            valu, indx = s_msgpack.un(byts)

            yield buid, valu