```

In this case, the `startup` event handler function will initialize the items "database" (just a `dict`) with some values.

You can add more than one event handler function.

And your application won't start receiving requests until all the `startup` event handlers have completed.

### `shutdown` event

To add a function that should be run when the application is shutting down, declare it with the event `"shutdown"`:

  repeated Event items = 2;
}

// EventSeries contain information on series of events, i.e. thing that was/is happening
// continuously for some time. How often to update the EventSeries is up to the event reporters.
// The default event reporter in "k8s.io/client-go/tools/events/event_broadcaster.go" shows
// how this struct is updated on heartbeats and can guide customized reporter implementations.
message EventSeries {

Diese Funktionen können mit `async def` oder normalem `def` deklariert werden.

### `startup`-Event

Um eine Funktion hinzuzufügen, die vor dem Start der Anwendung ausgeführt werden soll, deklarieren Sie diese mit dem Event `startup`:

```Python hl_lines="8"
{!../../../docs_src/events/tutorial001.py!}
```

# Events testen: Hochfahren – Herunterfahren

Wenn Sie in Ihren Tests Ihre Event-Handler (`startup` und `shutdown`) ausführen wollen, können Sie den `TestClient` mit einer `with`-Anweisung verwenden:

```Python hl_lines="9-12  20-24"
{!../../../docs_src/app_testing/tutorial003.py!}

// Events have a limited retention time and triggers and messages may evolve
// with time.  Event consumers should not rely on the timing of an event
// with a given Reason reflecting a consistent underlying trigger, or the
// continued existence of events with that Reason.  Events should be
// treated as informative, best-effort, supplemental data.
message Event {
  // Standard object's metadata.

# OpenAPI Webhooks

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

## Webhooks steps

import okhttp3.Response

/**
 * An OkHttp EventListener, which logs call events. Can be applied as an
 * [event listener factory][OkHttpClient.eventListenerFactory].
 *
 * The format of the logs created by this class should not be considered stable and may change
 * slightly between releases. If you need a stable logging format, use your own event listener.
 */
class LoggingEventListener private constructor(

     * [Request.tag]. Use null to remove any existing tag assigned for [T].
     *
     * Use this API to attach timing, debugging, or other application data to a request so that
     * you may read it in interceptors, event listeners, or callbacks.
     */
    @JvmName("reifiedTag")
    inline fun <reified T : Any> tag(tag: T?): Builder = tag(T::class, tag)

    /**

``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

            - include_router
            - get
            - put
            - post
            - delete
            - options
            - head
            - patch
            - trace