@Override
    public Collection<? extends ImmutableSDField> getStructFields() {
        return importedComplexField.getNestedFields().stream().map(field -> field.asImmutableSDField()).toList();
    }
Wraps {@link ImportedComplexField} as {@link ImmutableSDField}.
config-model/src/main/java/com/yahoo/schema/document/ImmutableImportedComplexSDField.java