public function version(): int
    {
        $versions = [
            static::VERSION_TIME,
            static::VERSION_DCE,
            static::VERSION_MD5,
            static::VERSION_RANDOM,
            static::VERSION_SHA1
        ];

        $version = (int) hexdec(substr($this->timeHiAndVersion, 0, 1));

        if (in_array($version, $versions, true)) {
            return $version;
        }

        return static::VERSION_UNKNOWN;
    }