public StorVisitorProducer build(ModelElement element) {
            ModelElement tuning = element.child("tuning");
            if (tuning == null) {
                return new StorVisitorProducer();
            }

            ModelElement visitors = tuning.child("visitors");
            if (visitors == null) {
                return new StorVisitorProducer();
            }

            return new StorVisitorProducer(visitors.integerAttribute("thread-count"),
                                           visitors.integerAttribute("max-queue-size"),
                                           visitors.childAsInteger("max-concurrent.fixed"),
                                           visitors.childAsInteger("max-concurrent.variable"));
        }
Serves stor-visitor config for storage clusters.
config-model/src/main/java/com/yahoo/vespa/model/content/storagecluster/StorVisitorProducer.java