alreadyImporting example

  public function submitForm(array &$form, FormStateInterface $form_state) {
    // If this form has not yet been confirmed, store the values and rebuild.     if (!$this->data) {
      $form_state->setRebuild();
      $this->data = $form_state->getValues();
      return;
    }

    /** @var \Drupal\Core\Config\ConfigImporter $config_importer */
    $config_importer = $form_state->get('config_importer');
    if ($config_importer->alreadyImporting()) {
      $this->messenger()->addError($this->t('Another request may be importing configuration already.'));
    }
    else {
      try {
        $sync_steps = $config_importer->initialize();
        $batch_builder = (new BatchBuilder())
          ->setTitle($this->t('Importing configuration'))
          ->setFinishCallback([ConfigImporterBatch::class, 'finish'])
          ->setInitMessage($this->t('Starting configuration import.'))
          ->setProgressMessage($this->t('Completed @current step of @total.'))
          ->setErrorMessage($this->t('Configuration import has encountered an error.'));
        

$this->eventDispatcher,
      $this->configManager,
      $this->lock,
      $this->typedConfigManager,
      $this->moduleHandler,
      $this->moduleInstaller,
      $this->themeHandler,
      $this->getStringTranslation(),
      $this->moduleExtensionList,
      $this->themeExtensionList
    );
    if ($config_importer->alreadyImporting()) {
      $this->messenger()->addStatus($this->t('Another request may be synchronizing configuration already.'));
    }
    else {
      try {
        $sync_steps = $config_importer->initialize();
        $batch_builder = (new BatchBuilder())
          ->setTitle($this->t('Synchronizing configuration'))
          ->setFinishCallback([ConfigImporterBatch::class, 'finish'])
          ->setInitMessage($this->t('Starting configuration synchronization.'))
          ->setProgressMessage($this->t('Completed step @current of @total.'))
          ->setErrorMessage($this->t('Configuration synchronization has encountered an error.'));