ProxyConfigSelector proxyConfigSelector() {
        return proxyConfigSelector;
    }
Returns a new {@link Bootstrap} for connecting to a {@link io.netty.channel.unix.DomainSocketAddress}.
The returned {@link Bootstrap} has its {@link ChannelFactory}, {@link AddressResolverGroup} and
socket options pre-configured.
core/src/main/java/com/linecorp/armeria/client/HttpClientFactory.java