private void initializeProducer(AnyConfigProducer child, DeployState deployState, Element producerSpec) {
            UserConfigRepo userConfigs = UserConfigBuilder.build(producerSpec, deployState, deployState.getDeployLogger());
            // TODO: must be made to work:
            //userConfigs.applyWarnings(child);
            log.log(Level.FINE, () -> "Adding user configs " + userConfigs + " for " + producerSpec);
            child.mergeUserConfigs(userConfigs);
        }
Base class for builders of producers using DOM. The purpose is to always
include hostalias, baseport and user config overrides generically.

@param <T> the type of producer to build
@param <P> the child type held by the parent of the new producer, usually AnyConfigProducer
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/VespaDomBuilder.java