docs: @BetaApi
    public final Operation setUrlMapTargetHttpProxy(
        ProjectTargetHttpProxyName targetHttpProxy, UrlMapReference urlMapReferenceResource) {
  
      SetUrlMapTargetHttpProxyHttpRequest request =
          SetUrlMapTargetHttpProxyHttpRequest.newBuilder()
              .setTargetHttpProxy(targetHttpProxy == null ? null : targetHttpProxy.toString())
              .setUrlMapReferenceResource(urlMapReferenceResource)
              .build();
      return setUrlMapTargetHttpProxy(request);
    }