WP_REST_Controller::update_additional_fields_for_object( object $data_object, WP_REST_Request $request ): true|WP_Error

455	protected function update_additional_fields_for_object( $data_object, $request ) {456		$additional_fields = $this->get_additional_fields();457 458		foreach ( $additional_fields as $field_name => $field_options ) {459			if ( ! $field_options['update_callback'] ) {460				continue;461			}462 463			// Don't run the update callbacks if the data wasn't passed in the request.464			if ( ! isset( $request[ $field_name ] ) ) {465				continue;466			}467 468			$result = call_user_func(469				$field_options['update_callback'],470				$request[ $field_name ],471				$data_object,472				$field_name,473				$request,474				$this->get_object_type()475			);476 477			if ( is_wp_error( $result ) ) {478				return $result;479			}480		}481 482		return true;483	}