thanks for your reply when we proces udp flow,we passed (NWHostEndpoint * )udp_flow.localEndpoint to flow open api。is that right？

we also test passed the endpoint like : NWHostEndpoint* endpoint = [NWHostEndpoint endpointWithHostname:@"0.0.0.0" port:@"0"]; and passed nil to open api. also cause net.inet.udp.pcbcount increased

after open the flow we create a bsd socket to proxy the flow request.