Como sempre, no FastAPI você pode combinar `def` e `async def` conforme necessário.

    Se você precisar de uma atualização sobre quando usar qual, confira a seção _"Com pressa?"_ na documentação sobre [`async` e `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

9. Esta *função de operação de rota* não está retornando dataclasses (embora pudesse), mas uma lista de dicionários com dados internos.

Вона може бути асинхронною `async def` або звичайною `def` функцією – **FastAPI** обробить її правильно.

У нашому випадку функція записує у файл (імітуючи надсилання email).

І оскільки операція запису не використовує `async` та `await`, ми визначаємо функцію як звичайну `def`:

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Додавання фонової задачі

```Python
with open("file.txt") as file:
    file.read()
```
최근 버전의 파이썬에서는 **비동기 컨텍스트 매니저**도 있습니다. 이를 `async with`와 함께 사용합니다:

```Python
async with lifespan(app):
    await do_stuff()
```

컨텍스트 매니저나 위와 같은 비동기 컨텍스트 매니저를 만들면, `with` 블록에 들어가기 전에 `yield` 이전의 코드가 실행되고, `with` 블록을 벗어난 후에는 `yield` 이후의 코드가 실행됩니다.

위의 코드 예제에서는 직접 사용하지 않고, FastAPI에 전달하여 사용하도록 합니다.

version: 2
updates:
# TODO(b/170636568): Enable Maven updates? Perhaps wait until we can more
# easily import the generated PRs into our internal repo.
#  - package-ecosystem: "maven"
#    directory: "/"
#    schedule:
#      interval: "weekly"
#    groups:
#      dependencies:
#        applies-to: version-updates
#        patterns:
#          - "*"
#  - package-ecosystem: "maven"
#    directory: "/android"
#    schedule:

  }

  /** For testing: force this web socket to release its threads. */
  @Throws(InterruptedException::class)
  fun tearDown() {
    taskQueue.shutdown()
    taskQueue.idleLatch().await(10, TimeUnit.SECONDS)
  }

  @Synchronized fun sentPingCount(): Int = sentPingCount

  @Synchronized fun receivedPingCount(): Int = receivedPingCount

        override fun responseHeadersEnd(
          call: Call,
          response: Response,
        ) {
          try {
            // Wait for the server to send the duplex response before acting on the 301 response
            // and resetting the stream.
            duplexResponseSent.await()
          } catch (e: InterruptedException) {
            throw AssertionError()
          }

   * than the given time. The manager will become healthy after all the component services have
   * reached the {@linkplain State#RUNNING running} state.
   *
   * @param timeout the maximum time to wait
   * @throws TimeoutException if not all of the services have finished starting within the deadline
   * @throws IllegalStateException if the service manager reaches a state from which it cannot

   */
  void awaitRunning();

  /**
   * Waits for the {@link Service} to reach the {@linkplain State#RUNNING running state} for no more
   * than the given time.
   *
   * @param timeout the maximum time to wait
   * @throws TimeoutException if the service has not reached the given state within the deadline
   * @throws IllegalStateException if the service reaches a state from which it is not possible to

				return err
			}
		}

		header, err := tarReader.Next()
		switch {
		// if no more files are found return
		case err == io.EOF:
			wg.Wait()
			return asyncErr

		// return any other error
		case err != nil:
			wg.Wait()
			extra := ""
			if n > 0 {
				extra = fmt.Sprintf(" after %d successful object(s)", n)
			}
			return fmt.Errorf("tar file error: %w%s", err, extra)

   * numElements} elements are not available, it will wait for them up to the specified timeout.
   *
   * @param q the blocking queue to be drained
   * @param buffer where to add the transferred elements
   * @param numElements the number of elements to be waited for
   * @param timeout how long to wait before giving up
   * @return the number of elements transferred