public function use_default_handler( HandlerInterface $handler = NULL ) {

		static $done = FALSE;
		if ( $done ) {
			return $this;
		}

		$done = TRUE;

		add_action(
			HandlersRegistry::ACTION_REGISTER,
			function ( HandlersRegistry $registry ) use ( $handler ) {

				$handler = DefaultHandlerFactory::with_default_handler( $handler )
					->create_default_handler();

				$registry->add_handler( $handler, HandlersRegistry::DEFAULT_NAME );
			},
			1
		);

		return $this;
	}