public function addByHttpCode(int $code): self
    {
        $serverProtocol = filter_input(
            \INPUT_SERVER,
            'SERVER_PROTOCOL',
            \FILTER_SANITIZE_STRING
        );
        $protocol = !empty($serverProtocol) ? $serverProtocol : 'HTTP/1.1';
        $sHeader   = "{$protocol} {$code} ".self::getHTTPExplanationByCode($code);
        return $this->add($sHeader);
    }