@Throws(IOException::class)
  fun peekTrailers(): Headers?

  /**
   * Cancel this stream. Resources held by this stream will be cleaned up, though not synchronously.
   * That may happen later by the connection pool thread.
   */
  fun cancel()

  /**
   * Carries an exchange. This is usually a connection, but it could also be a connect plan for

            }
        };
    }

    // ===================================================================================
    //                                                                        Asynchronous
    //                                                                        ============
    protected void async(final AsyncManager asyncManager, final Runnable runnable) {

In diesem Abschnitt werden wir sehen, wie man andere Middlewares verwendet.

## ASGI-Middleware hinzufügen

Da **FastAPI** auf Starlette basiert und die <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr>-Spezifikation implementiert, können Sie jede ASGI-Middleware verwenden.

		}
	}

	for i, version := range x.versions {
		if version.header.VersionID != uv || version.header.Type != ObjectType {
			continue
		}
		// if uv has tiered content we add a
		// free-version to track it for asynchronous
		// deletion via scanner.
		ver, err := x.getIdx(i)
		if err != nil {
			return err
		}

		if freeVersion, toFree := ver.ObjectV2.InitFreeVersion(fi); toFree {
			return x.addVersion(freeVersion)

 *
 * Other exception types cancel the current call:
 *
 *  * For synchronous calls made with [Call.execute], the exception is propagated to the caller.
 *
 *  * For asynchronous calls made with [Call.enqueue], an [IOException] is propagated to the caller
 *    indicating that the call was canceled. The interceptor's exception is delivered to the current

Calls are executed in one of two ways:

 * **Synchronous:** your thread blocks until the response is readable.
 * **Asynchronous:** you enqueue the request on any thread, and get [called back](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-callback/) on another thread when the response is readable.

& ⤴️ 👆 ✍ ❔ 🍵 [⚜ ⏮️ `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

👉 📄 👥 🔜 👀 ❔ ⚙️ 🎏 🛠️.

## ❎ 🔫 🛠️

**FastAPI** ⚓️ 🔛 💃 &amp; 🛠️ <abbr title="Asynchronous Server Gateway Interface">🔫</abbr> 🔧, 👆 💪 ⚙️ 🙆 🔫 🛠️.

🛠️ 🚫 ✔️ ⚒ FastAPI ⚖️ 💃 👷, 📏 ⚫️ ⏩ 🔫 🔌.

🏢, 🔫 🛠️ 🎓 👈 ⌛ 📨 🔫 📱 🥇 ❌.

, 🧾 🥉-🥳 🔫 🛠️ 👫 🔜 🎲 💬 👆 🕳 💖:

```Python

        // Shutdown scheduler
        scheduler.shutdown();

        // Close RPC client
        if (rpcClient != null) {
            rpcClient.close();
        }
    }

    /**
     * Starts asynchronous notification monitoring for a registration.
     *
     * @param registration the witness registration
     */
    private void startAsyncNotificationMonitoring(WitnessRegistration registration) {

        }

        /**
         * Gets the future for asynchronous notification completion
         * @return the notification future
         */
        public CompletableFuture<Void> getNotificationFuture() {
            return notificationFuture;
        }

        /**
         * Sets the future for asynchronous notification completion
         * @param future the notification future to set

Nesta seção, veremos como usar outros middlewares.

## Adicionando middlewares ASGI

Como o **FastAPI** é baseado no Starlette e implementa a especificação <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr>, você pode usar qualquer middleware ASGI.

O middleware não precisa ser feito para o FastAPI ou Starlette para funcionar, desde que siga a especificação ASGI.