Cake\Network\Response::_getUTCDate PHP Method

    protected function _getUTCDate($time = null)
    {
        if ($time instanceof DateTime) {
            $result = clone $time;
        } elseif (is_int($time)) {
            $result = new DateTime(date('Y-m-d H:i:s', $time));
        } else {
            $result = new DateTime($time);
        }
        $result->setTimeZone(new DateTimeZone('UTC'));
        return $result;
    }