code: def _resolve_srv(self):
          
          resolver = self.settings["dns_resolver"] # pylint: disable=W0621
          self._set_state("resolving-srv")
          self.event(ResolvingSRVEvent(self._dst_name, self._dst_service))
          resolver.resolve_srv(self._dst_name, self._dst_service, "tcp",
                                                      callback = self._got_srv)
docs: Start resolving the SRV record.