@Override
    public void visitMembers(ObjectVisitor visitor) {
        super.visitMembers(visitor);
        visitor.visit("maxGroups", maxGroups);
        visitor.visit("precision", precision);
        visitor.visit("classify", classify);
        visitor.visit("filter", filter);
        visitor.visit("collect", collect);
    }
<p>Tell if ordering will need results collected in children.</p>

@return If deeper resultcollection is needed.
searchlib/src/main/java/com/yahoo/searchlib/aggregation/GroupingLevel.java