protected static function ourStrlen($str)
    {
        // Premature optimization: cache the function_exists() result
        static $exists = null;
        if ($exists === null) {
            $exists = \function_exists('\\mb_strlen');
        }

        // If it exists, we need to make sure we're using 8bit mode
        if ($exists) {
            return \mb_strlen($str, '8bit');
        }
        return \strlen($str);
    }