@Override
    public void getConfig(ProtonConfig.Builder builder) {
        if (searchNode != null) searchNode.getConfig(builder);
    }
Class representing the tuning config used for a search cluster.
Take a look at proton.def and vespa doc for detailed explanations.

@author geirst
config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java