public function insertBefore($matchingTitle, $title, $url = null, array $options = [])
    {
        $key = $this->findCrumb($matchingTitle);

        if ($key === null) {
            throw new LogicException(sprintf("No crumb matching '%s' could be found.", $matchingTitle));
        }

        return $this->insertAt($key, $title, $url, $options);
    }