notificationEventsErrorsTotalMD     = NewCounterMD(notificationEventsErrorsTotal, "Events that were failed to be sent to the targets")
	notificationEventsSentTotalMD       = NewCounterMD(notificationEventsSentTotal, "Total number of events sent to the targets")
	notificationEventsSkippedTotalMD    = NewCounterMD(notificationEventsSkippedTotal, "Events that were skipped to be sent to the targets due to the in-memory queue being full")
)

Sie definieren auch auf irgendeine Weise, zu welchen **Momenten** Ihre Anwendung diese Requests oder Events sendet.

Und **Ihre Benutzer** definieren auf irgendeine Weise (zum Beispiel irgendwo in einem Web-Dashboard) die **URL**, an die Ihre Anwendung diese Requests senden soll.

      throw AssertionError("full event sequence: $fullEventSequence", e)
    }
  }

  /**
   * Remove and return the next event from the recorded sequence.
   *
   * @param eventClass a class to assert that the returned event is an instance of, or null to
   *     take any event class.
   * @param elapsedMs the time in milliseconds elapsed since the immediately-preceding event, or
   *     -1L to take any duration.
   */

  /**
   * Invoked when an event source has been accepted by the remote peer and may begin transmitting
   * events.
   */
  open fun onOpen(
    eventSource: EventSource,
    response: Response,
  ) {
  }

  /**
   * Invoked when a new event has been sent to the client.
   *
   * @param id The `id` line of the event, might be null.
   * @param type The `event` line of the event, might be null.

    } else {
      eventSequence.forEach loop@{
        when (e.closes(it)) {
          null -> return // no open event
          true -> return // found open event
          false -> return@loop // this is not the open event so continue
        }
      }
      fail<Any>("event $e without matching start event")
    }
  }

  override fun proxySelectStart(
    call: Call,
    url: HttpUrl,

https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

con un JSON body de:

```JSON
{
    "id": "2expen51ve",
    "customer": "Mr. Richie Rich",
    "total": "9999"
}
```

luego *tu API* procesará la factura, y en algún momento después, enviará un request de callback al `callback_url` (la *API externa*):

```
https://www.external.org/events/invoices/2expen51ve
```

/// tip

Note that we're using async/await with the new `AsyncClient` - the request is asynchronous.

///

/// warning

If your application relies on lifespan events, the `AsyncClient` won't trigger these events. To ensure they are triggered, use `LifespanManager` from <a href="https://github.com/florimondmanca/asgi-lifespan#usage" class="external-link" target="_blank">florimondmanca/asgi-lifespan</a>.

///

/// tip | Tipp

Beachten Sie, dass wir async/await mit dem neuen `AsyncClient` verwenden – der Request ist asynchron.

///

/// warning | Achtung

import jakarta.annotation.Resource;

/**
 * Action class for handling document redirection requests.
 * This action processes "go" requests that redirect users to specific documents
 * while tracking click events and handling various URL types including file system paths.
 */
public class GoAction extends FessSearchAction {

    /**
     * Default constructor for GoAction.
     */
    public GoAction() {
        super();

```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

⏮️ 🎻 💪:

```JSON
{
    "id": "2expen51ve",
    "customer": "Mr. Richie Rich",
    "total": "9999"
}
```

⤴️ *👆 🛠️* 🔜 🛠️ 🧾, & ☝ ⏪, 📨 ⏲ 📨 `callback_url` ( *🔢 🛠️*):

```
https://www.external.org/events/invoices/2expen51ve
```

⏮️ 🎻 💪 ⚗ 🕳 💖:

```JSON
{