// We post the event, but our Executor will not deliver it until instructed.
    bus.post(EVENT);

    List<String> events = catcher.getEvents();
    assertTrue("No events should be delivered synchronously.", events.isEmpty());

    // Now we find the task in our Executor and explicitly activate it.
    List<Runnable> tasks = executor.getTasks();
    assertEquals("One event dispatch task should be queued.", 1, tasks.size());

В этом разделе посмотрим, как использовать другие middleware.

## Добавление ASGI middleware { #adding-asgi-middlewares }

Так как **FastAPI** основан на Starlette и реализует спецификацию <abbr title="Asynchronous Server Gateway Interface – Асинхронный шлюзовой интерфейс сервера">ASGI</abbr>, вы можете использовать любое ASGI middleware.

///

## Andere asynchrone Funktionsaufrufe { #other-asynchronous-function-calls }

  @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

Here's a little bit of that history.

## Alternatives { #alternatives }

I have been creating APIs with complex requirements for several years (Machine Learning, distributed systems, asynchronous jobs, NoSQL databases, etc), leading several teams of developers.

As part of that, I needed to investigate, test and use many alternatives.

The history of **FastAPI** is in great part the history of its predecessors.

///

/// tip

If you want to call `async` functions in your tests apart from sending requests to your FastAPI application (e.g. asynchronous database functions), have a look at the [Async Tests](../advanced/async-tests.md){.internal-link target=_blank} in the advanced tutorial.

///

## Separating tests { #separating-tests }

///

## Outras Chamadas de Funções Assíncronas { #other-asynchronous-function-calls }

En esta sección veremos cómo usar otros middlewares.

## Agregando middlewares ASGI { #adding-asgi-middlewares }

Como **FastAPI** está basado en Starlette e implementa la especificación <abbr title="Asynchronous Server Gateway Interface – Interfaz de puerta de enlace de servidor asíncrona">ASGI</abbr>, puedes usar cualquier middleware ASGI.

   dropped in 2.0.

## Version 1.5.4

_2014-04-14_

 * Drop ALPN support in Android. There's a concurrency bug in all
   currently-shipping versions.
 * Support asynchronous disconnects by breaking the socket only. This should
   prevent flakiness from multiple threads concurrently accessing a stream.

## Version 1.5.3

_2014-03-29_

   */
  fun cancel()

  fun interface Factory {
    /**
     * Creates a new web socket and immediately returns it. Creating a web socket initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must either close or cancel the returned web socket when it is no longer
     * in use.
     */