code: public function getProvisionUri(User $user, Request $request): string
      {
          $issuer = rawurlencode($request->getSchemeAndHttpHost());
  
          return sprintf(
                  'otpauth://totp/%s:%s?secret=%s&issuer=%s',
                  $issuer,
                  rawurlencode($user->getUsername()).'@'.$issuer,
                  $this->getUpperUnpaddedSecretForUser($user),
                  $issuer
          );
      }
docs: Generates the TOTP provision URI.