public static function header($name = null)
    {
        if (self::$reqHeaders === null) {
            self::generate();
        }

        if (is_string($name)) {
            $name = strtolower($name);
            return isset(self::$reqHeadersLower[$name]) ? self::$reqHeadersLower[$name] : false;
        }

        return self::$reqHeaders;
    }