private void validateObject(String name) {
        if (configDefinition != null) {
            configDefinition.verify(name);
        }
    }
Get a new payload builder for a config struct, which can be used to add inner values to that struct.

@param name name of the struct to create
@return a payload builder corresponding to the name
config/src/main/java/com/yahoo/vespa/config/ConfigPayloadBuilder.java