code: def _resolve_hostname(self):
          
          self._set_state("resolving-hostname")
          resolver = self.settings["dns_resolver"] # pylint: disable=W0621
          logger.debug("_dst_nameports: {0!r}".format(self._dst_nameports))
          name, port = self._dst_nameports.pop(0)
          self._dst_hostname = name
          resolver.resolve_address(name, callback = partial(
                                  self._got_addresses, name, port),
                                  allow_cname = self._dst_service is None)
          self.event(ResolvingAddressEvent(name))
docs: Start hostname resolution for the next name to try.
  
          [called with `lock` acquired]