renderMissingMediaIndicator example

$view_mode = NULL;
      if ($view_mode_id !== EntityDisplayRepositoryInterface::DEFAULT_DISPLAY_MODE) {
        $view_mode = $this->entityRepository->loadEntityByConfigTarget('entity_view_mode', "media.$view_mode_id");
        if (!$view_mode) {
          $this->loggerFactory->get('media')->error('During rendering of embedded media: the view mode "@view-mode-id" does not exist.', ['@view-mode-id' => $view_mode_id]);
        }
      }

      $build = $media && ($view_mode || $view_mode_id === EntityDisplayRepositoryInterface::DEFAULT_DISPLAY_MODE)
        ? $this->renderMedia($media, $view_mode_id, $langcode)
        : $this->renderMissingMediaIndicator();

      if (empty($build['#attributes']['class'])) {
        $build['#attributes']['class'] = [];
      }
      // Any attributes not consumed by the filter should be carried over to the       // rendered embedded entity. For example, `data-align` and `data-caption`       // should be carried over, so that even when embedded media goes missing,       // at least the caption and visual structure won't get lost.       foreach ($node->attributes as $attribute) {
        if ($attribute->nodeName == 'class') {
          // We don't want to overwrite the existing CSS class of the embedded