code: @Override
      protected final AddressResolver<InetSocketAddress> newAddressResolver(EventLoop eventLoop,
                                                                            NameResolver<InetAddress> resolver)
              throws Exception {
          return new RoundRobinInetAddressResolver(eventLoop, resolver).asAddressResolver();
      }
docs: We need to override this method, not
  {@link #newNameResolver(EventLoop, ChannelFactory, DnsServerAddressStreamProvider)},
  because we need to eliminate possible caching of {@link io.netty.resolver.NameResolver#resolve}
  by {@link InflightNameResolver} created in
  {@link #newResolver(EventLoop, ChannelFactory, DnsServerAddressStreamProvider)}.