e: IOException,
  )

  /**
   * Called when the HTTP response was successfully returned by the remote server. The callback may
   * proceed to read the response body with [Response.body]. The response is still live until its
   * response body is [closed][ResponseBody]. The recipient of the callback may consume the response
   * body on another thread.
   *

	}
	// Only frames in the test package are checked.
	want := []string{
		"test._Cfunc_backtrace",
		"test.testCallbackCallersSEH.func1.1",
		"test.testCallbackCallersSEH.func1",
		"test.goCallback",
		"test._Cfunc_callback",
		"test.nestedCall.func1",
		"test.nestedCall",
		"test.testCallbackCallersSEH",
		"test.TestCallbackCallersSEH",
	}
	pc := make([]uintptr, 100)
	n := 0
	nestedCall(func() {

class CustomModel(BaseModel):
    a: int


app = FastAPI()

callback_router = APIRouter(default_response_class=JSONResponse)


@callback_router.get(
    "{$callback_url}/callback/", responses={400: {"model": CustomModel}}
)
def callback_route():
    pass  # pragma: no cover


@app.post("/", callbacks=callback_router.routes)
def main_route(callback_url: HttpUrl):
    pass  # pragma: no cover

	var callbacks []*callback
	removedMap := map[string]bool{}
	for _, callback := range p.callbacks {
		if callback.match == nil || callback.match(p.db) {
			callbacks = append(callbacks, callback)
		}
		if callback.remove {
			removedMap[callback.name] = true
		}
	}

	if len(removedMap) > 0 {
		callbacks = removeCallbacks(callbacks, removedMap)
	}
	p.callbacks = callbacks

		},
		{
			callbacks: []callback{{h: c1}, {h: c2}, {h: c3}, {h: c4}, {h: c5, before: "c4"}},
			results:   []string{"c1", "c2", "c3", "c5", "c4"},
		},
		{
			callbacks: []callback{{h: c1}, {h: c2}, {h: c3}, {h: c4, after: "c5"}, {h: c5}},
			results:   []string{"c1", "c2", "c3", "c5", "c4"},
		},
		{
			callbacks: []callback{{h: c1}, {h: c2}, {h: c3}, {h: c4, after: "c5"}, {h: c5, before: "c4"}},

### Einen Callback-`APIRouter` erstellen

Erstellen Sie zunächst einen neuen `APIRouter`, der einen oder mehrere Callbacks enthält.

```Python hl_lines="3  25"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

### Die Callback-*Pfadoperation* erstellen

callback_router3 = APIRouter()


@callback_router3.get("/")
async def callback3(level3: str):
    pass  # pragma: nocover


callback_router4 = APIRouter()


@callback_router4.get("/")
async def callback4(level4: str):
    pass  # pragma: nocover


callback_router5 = APIRouter()


@callback_router5.get("/")
async def callback5(level5: str):
    pass  # pragma: nocover

Now use the parameter `callbacks` in *your API's path operation decorator* to pass the attribute `.routes` (that's actually just a `list` of routes/*path operations*) from that callback router:

```Python hl_lines="35"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip

⚫️ 🔜 ✔️ *➡ 🛠️* 👈 🔜 📨 `Invoice` 💪, & 🔢 🔢 `callback_url` 👈 🔜 🔌 📛 ⏲.

👉 🍕 📶 😐, 🌅 📟 🎲 ⏪ 😰 👆:

```Python hl_lines="9-13  36-53"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip
     `callback_url` 🔢 🔢 ⚙️ Pydantic <a href="https://docs.pydantic.dev/latest/concepts/types/#urls" class="external-link" target="_blank">📛</a> 🆎.

🕴 🆕 👜 `callbacks=messages_callback_router.routes` ❌ *➡ 🛠️ 👨‍🎨*. 👥 🔜 👀 ⚫️❔ 👈 ⏭.

                        },
                        "callbacks": {
                            "event_callback": {
                                "{$callback_url}/events/{$request.body.title}": {
                                    "get": {
                                        "summary": "Event Callback",
                                        "operationId": "event_callback__callback_url__events___request_body_title__get",