void createComplexTypes() {
            var toCreate = new ArrayList<>(factoryByIdx.keySet());
            for (var dataTypeId : toCreate) {
                var type = getOrCreateType(dataTypeId);
                assert(type != null);
            }
        }
One-shot configuration; should be called on a newly constructed manager
document/src/main/java/com/yahoo/document/DocumentTypeManagerConfigurer.java