public static function updateVisibilityFinishedCallback($success, array $results, array $operations) {
    $messenger = \Drupal::messenger();
    if ($success) {
      // Here we could do something meaningful with the results.
      // We just display the number of nodes we processed...
      $messenger->addStatus(t('Visibility of @count content item(s) updated.', ['@count' => count($results)]));
    }
    else {
      // An error occurred.
      // $operations contains the operations that remained unprocessed.
      $error_operation = reset($operations);
      $messenger->addError(
        t('An error occurred while processing @operation with arguments : @args',
          [
            '@operation' => $error_operation[0],
            '@args' => print_r($error_operation[0], TRUE),
          ]
        )
      );
    }
  }