public function destroy($removeCookie = true)
    {
        if (session_id()) {
            if ($removeCookie) {
                $path = $this->config()->get('cookie_path') ?: Director::baseURL();
                $domain = $this->config()->get('cookie_domain');
                $secure = $this->config()->get('cookie_secure');
                Cookie::force_expiry(session_name(), $path, $domain, $secure, true);
            }
            session_destroy();
        }
        // Clean up the superglobal - session_destroy does not do it.
        // http://nz1.php.net/manual/en/function.session-destroy.php
        unset($_SESSION);
        $this->data = null;
    }