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.

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
```

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
```

import org.apache.logging.log4j.core.impl.Log4jLogEvent;

/**
 * Log4j rewrite policy that converts ERROR level log events to WARN level for specified loggers.
 * This policy is useful for downgrading the severity of log events from certain loggers
 * to prevent them from being treated as critical errors.
 */

/// 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

   * EventListeners added by Interceptors will not see all events.
   */
  private val enforceOrder: Boolean = true,
) : EventListener() {
  val eventSequence: Deque<CallEvent> = ConcurrentLinkedDeque()

  private val forbiddenLocks = mutableListOf<Any>()

  /** The timestamp of the last taken event, used to measure elapsed time between events. */
  private var lastTimestampNs: Long? = null

 */
package okhttp3.sse

import okhttp3.Response

abstract class EventSourceListener {
  /**
   * 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.
   *

import okio.ByteString.Companion.toByteString

/**
 * Logs SSL keys to a log file, allowing Wireshark to decode traffic and be examined with http2
 * filter. The approach is to hook into JSSE log events for the messages between client and server
 * during handshake, and then take the agreed masterSecret from private fields of the session.
 *
 * Copy WireSharkKeyLoggerListener to your test code to use in development.
 *

   * EventListeners added by Interceptors will not see all events.
   */
  private val enforceOrder: Boolean = true,
) : ConnectionListener() {
  val eventSequence: Deque<ConnectionEvent> = ConcurrentLinkedDeque()

  private val forbiddenLocks = mutableSetOf<Any>()

  /** The timestamp of the last taken event, used to measure elapsed time between events. */
  private var lastTimestampNs: Long? = null