return v, ok
	}
	return cache.iamUserPolicyMap.Load(name)
}

// GroupNotificationHandler - updates in-memory cache on notification of
// change (e.g. peer notification for object storage and etcd watch
// notification).
func (store *IAMStoreSys) GroupNotificationHandler(ctx context.Context, group string) error {
	cache := store.lock()
	defer store.unlock()

   * evictEntry is called (once the lock is released).
   */
  void processPendingNotifications() {
    RemovalNotification<K, V> notification;
    while ((notification = removalNotificationQueue.poll()) != null) {
      try {
        removalListener.onRemoval(notification);
      } catch (Throwable e) {
        logger.log(Level.WARNING, "Exception thrown by removal listener", e);
      }
    }
  }

  // Element Mutation

  @Test
  public void addEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future
    // modifications to proxy methods)
    addNode(N1);
    addNode(N2);
    assertThat(networkAsMutableNetwork.addEdge(N1, N2, E12)).isTrue();
    assertThat(network.edges()).contains(E12);

  // Element Mutation

  @Test
  public void addEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future
    // modifications to proxy methods)
    addNode(N1);
    addNode(N2);
    assertThat(networkAsMutableNetwork.addEdge(N1, N2, E12)).isTrue();
    assertThat(network.edges()).contains(E12);

Then your API will (let's imagine):

* Send the invoice to some customer of the external developer.
* Collect the money.
* Send a notification back to the API user (the external developer).
    * This will be done by sending a POST request (from *your API*) to some *external API* provided by that external developer (this is the "callback").

## The normal **FastAPI** app

	}:
	case <-list.ctx.Done():
		list.eventsSkipped.Add(int64(len(list.queue)))
		return
	default:
		list.eventsSkipped.Add(1)
		err := fmt.Errorf("concurrent target notifications exceeded %d, configured notification target is too slow to accept events for the incoming request rate", maxConcurrentAsyncSend)
		for id := range targetIDset {
			reqInfo := &logger.ReqInfo{}
			reqInfo.AppendTags("targetID", id.String())

		}
	}

	return nil
}

// To obtain a nats connection from args.
func (n NATSArgs) connectNats() (*nats.Conn, error) {
	connOpts := []nats.Option{nats.Name("Minio Notification"), nats.MaxReconnects(-1)}
	if n.Username != "" && n.Password != "" {
		connOpts = append(connOpts, nats.UserInfo(n.Username, n.Password))
	}
	if n.UserCredentials != "" {

// This list should be kept alphabetically sorted, do not hastily edit.
var resourceList = []string{
	"acl",
	"cors",
	"delete",
	"encryption",
	"legal-hold",
	"lifecycle",
	"location",
	"logging",
	"notification",
	"partNumber",
	"policy",
	"requestPayment",
	"response-cache-control",
	"response-content-disposition",
	"response-content-encoding",
	"response-content-language",
	"response-content-type",

   * will never throw {@link ConcurrentModificationException}, and guarantees to traverse elements
   * as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect
   * any modifications subsequent to construction.
   *
   * @return an iterator over the elements in this queue
   */
  @CanIgnoreReturnValue // pushed down from class to method
  @Override
  public Iterator<E> iterator() {

MINIO_API_OBJECT_MAX_VERSIONS             (number)    set max allowed number of versions per object (default: '9223372036854775807')
```

#### Notifications

Notification targets supported by MinIO are in the following list. To configure individual targets please refer to more detailed documentation [here](https://min.io/docs/minio/linux/administration/monitoring.html#bucket-notifications).

```