public void verifyComplete() {
        if (path == null) throw new IllegalStateException("HTTP requests must have a path set. Use '/' for top level");
        if (httpOperation == null) throw new IllegalStateException("HTTP requests must have an HTTP method defined");
    }
Create a copy of this request, and override what is specified in the input in the new request.
clustercontroller-utils/src/main/java/com/yahoo/vespa/clustercontroller/utils/communication/http/HttpRequest.java