ChildCountField example

new FloatField('width', 'width'))->addFlags(new ApiAware(), new Inherited()),
            (new FloatField('height', 'height'))->addFlags(new ApiAware(), new Inherited()),
            (new FloatField('length', 'length'))->addFlags(new ApiAware(), new Inherited()),
            (new DateTimeField('release_date', 'releaseDate'))->addFlags(new ApiAware(), new Inherited()),
            (new FloatField('rating_average', 'ratingAverage'))->addFlags(new ApiAware(), new WriteProtected(), new Inherited()),
            (new ListField('category_tree', 'categoryTree', IdField::class))->addFlags(new ApiAware(), new Inherited(), new WriteProtected()),
            (new ManyToManyIdField('property_ids', 'propertyIds', 'properties'))->addFlags(new ApiAware(), new Inherited()),
            (new ManyToManyIdField('option_ids', 'optionIds', 'options'))->addFlags(new ApiAware(), new Inherited()),
            (new ManyToManyIdField('stream_ids', 'streamIds', 'streams'))->addFlags(new ApiAware(), new Inherited()),
            (new ManyToManyIdField('tag_ids', 'tagIds', 'tags'))->addFlags(new Inherited()),
            (new ManyToManyIdField('category_ids', 'categoryIds', 'categories'))->addFlags(new ApiAware(), new Inherited()),
            (new ChildCountField())->addFlags(new ApiAware()),
            (new BoolField('custom_field_set_selection_active', 'customFieldSetSelectionActive'))->addFlags(new Inherited()),
            (new IntField('sales', 'sales'))->addFlags(new ApiAware(), new WriteProtected()),
            (new ListField('states', 'states', StringField::class))->addFlags(new ApiAware(), new WriteProtected()),
            (new OneToManyAssociationField('downloads', ProductDownloadDefinition::class, 'product_id'))->addFlags(new ApiAware(), new CascadeDelete()),

            (new TranslatedField('metaDescription'))->addFlags(new ApiAware(), new Inherited()),
            (new TranslatedField('name'))->addFlags(new ApiAware(), new Inherited(), new SearchRanking(SearchRanking::HIGH_SEARCH_RANKING)),
            (new TranslatedField('keywords'))->addFlags(new ApiAware(), new Inherited()),
            (new TranslatedField('description'))->addFlags(new ApiAware(), new Inherited()),
            (new TranslatedField('metaTitle'))->addFlags(new ApiAware(), new Inherited()),
            (new TranslatedField('packUnit'))->addFlags(new ApiAware(), new Inherited()),
            (

protected function defineFields(): FieldCollection
    {
        return new FieldCollection(
            [
                (new StringField('string_field', 'stringField'))->addFlags(new ApiAware()),
                (new IntField('int_field', 'intField'))->addFlags(new ApiAware()),
                (new FloatField('float_field', 'floatField'))->addFlags(new ApiAware()),
                (new BoolField('bool_field', 'boolField'))->addFlags(new ApiAware()),
                (new IdField('id_field', 'idField'))->addFlags(new ApiAware()),
                (new StringField('i_am_a_new_field', 'i_am_a_new_field'))->addFlags(new ApiAware(), new Since('6.3.9.9')),
                (new ChildCountField())->addFlags(new ApiAware()),

                (new StringField('required_field', 'requiredField'))->addFlags(new ApiAware(), new Required()),
                (new StringField('read_only_field', 'readOnlyField'))->addFlags(new ApiAware(), new WriteProtected()),
            ]
        );
    }
}

new FkField('after_category_id', 'afterCategoryId', self::class))->addFlags(new ApiAware()),
            (new ReferenceVersionField(self::class, 'after_category_version_id'))->addFlags(new ApiAware(), new Required()),

            (new FkField('media_id', 'mediaId', MediaDefinition::class))->addFlags(new ApiAware()),

            (new BoolField('display_nested_products', 'displayNestedProducts'))->addFlags(new ApiAware(), new Required()),
            new AutoIncrementField(),

            (new TranslatedField('breadcrumb'))->addFlags(new ApiAware(), new WriteProtected()),
            (new TreeLevelField('level', 'level'))->addFlags(new ApiAware()),
            (new TreePathField('path', 'path'))->addFlags(new ApiAware()),
            (new ChildCountField())->addFlags(new ApiAware()),

            (new StringField('type', 'type'))->addFlags(new ApiAware(), new Required()),
            (new StringField('product_assignment_type', 'productAssignmentType'))->addFlags(new ApiAware(), new Required()),
            (new BoolField('visible', 'visible'))->addFlags(new ApiAware()),
            (new BoolField('active', 'active'))->addFlags(new ApiAware()),

            (new BoolField('cmsPageIdSwitched', 'cmsPageIdSwitched'))->addFlags(new Runtime(), new ApiAware()),
            (new IntField('visibleChildCount', 'visibleChildCount'))->addFlags(new Runtime(), new ApiAware()),

            (new TranslatedField('name'))->addFlags(new ApiAware(), new SearchRanking(SearchRanking::HIGH_SEARCH_RANKING)),
            (new TranslatedField('customFields'))->addFlags(new ApiAware()),
            

protected function defineFields(): FieldCollection
    {
        return new FieldCollection(
            [
                (new StringField('string_field', 'stringField'))->addFlags(new ApiAware()),
                (new IntField('int_field', 'intField'))->addFlags(new ApiAware()),
                (new FloatField('float_field', 'floatField'))->addFlags(new ApiAware()),
                (new BoolField('bool_field', 'boolField'))->addFlags(new ApiAware()),
                (new IdField('id_field', 'idField'))->addFlags(new ApiAware()),
                (new StringField('i_am_a_new_field', 'i_am_a_new_field'))->addFlags(new ApiAware(), new Since('6.3.9.9')),
                (new ChildCountField())->addFlags(new ApiAware()),

                (new StringField('required_field', 'requiredField'))->addFlags(new ApiAware(), new Required()),
                (new StringField('read_only_field', 'readOnlyField'))->addFlags(new ApiAware(), new WriteProtected()),
                (new StringField('runtime_field', 'runtimeField'))->addFlags(new ApiAware(), new Runtime()),
            ]
        );
    }
}

protected function defineFields(): FieldCollection
    {
        return new FieldCollection([
            (new IdField('id', 'id'))->addFlags(new PrimaryKey(), new Required()),
            new BoolField('use_parent_configuration', 'useParentConfiguration'),
            (new FkField('media_folder_configuration_id', 'configurationId', MediaFolderConfigurationDefinition::class))->addFlags(new Required()),
            new FkField('default_folder_id', 'defaultFolderId', MediaDefaultFolderDefinition::class),
            new ParentFkField(self::class),
            new ParentAssociationField(self::class, 'id'),
            new ChildrenAssociationField(self::class),
            new ChildCountField(),
            new TreePathField('path', 'path'),
            (new OneToManyAssociationField('media', MediaDefinition::class, 'media_folder_id'))->addFlags(new SetNullOnDelete()),
            new OneToOneAssociationField('defaultFolder', 'default_folder_id', 'id', MediaDefaultFolderDefinition::class, false),
            new ManyToOneAssociationField('configuration', 'media_folder_configuration_id', MediaFolderConfigurationDefinition::class, 'id', false),
            (new StringField('name', 'name'))->addFlags(new SearchRanking(SearchRanking::HIGH_SEARCH_RANKING), new Required()),
            new CustomFields(),
        ]);
    }
}