def send_barrier_request(self):
        parser = self.dp.ofproto_parser
        req = parser.OFPBarrierRequest(self.dp)
        return self.send_msg(req)
send a BARRIER_REQUEST message.
dataset/ETHPy150Open osrg/ryu/ryu/tests/switch/tester.py/OpenFlowSw.send_barrier_request