FieldStorageDefinitionEvent example

$entity_type_id = $storage_definition->getTargetEntityTypeId();

    // @todo Forward this to all interested handlers, not only storage, once     // iterating handlers is possible: https://www.drupal.org/node/2332857.     $storage = $this->entityTypeManager->getStorage($entity_type_id);
    if ($storage instanceof FieldStorageDefinitionListenerInterface) {
      $storage->onFieldStorageDefinitionCreate($storage_definition);
    }

    $this->entityLastInstalledSchemaRepository->setLastInstalledFieldStorageDefinition($storage_definition);

    $this->eventDispatcher->dispatch(new FieldStorageDefinitionEvent($storage_definition), FieldStorageDefinitionEvents::CREATE);
    $this->entityFieldManager->clearCachedFieldDefinitions();
  }

  /** * {@inheritdoc} */
  public function onFieldStorageDefinitionUpdate(FieldStorageDefinitionInterface $storage_definition, FieldStorageDefinitionInterface $original) {
    $entity_type_id = $storage_definition->getTargetEntityTypeId();

    // @todo Forward this to all interested handlers, not only storage, once     // iterating handlers is possible: https://www.drupal.org/node/2332857.