async.setFuture(inner);
    async.cancel(false);
    assertTrue(inner.isCancelled());
    assertFalse(inner.wasInterrupted());
    assertThrows(CancellationException.class, () -> inner.get());
  }

  public void testCancel_beforeSet() throws Exception {
    SettableFuture<Object> async = SettableFuture.create();
    async.cancel(true);
    assertFalse(async.set(42));
  }

The first thing to notice, is that we are defining an async function with `yield`. This is very similar to Dependencies with `yield`.

{* ../../docs_src/events/tutorial003.py hl[14:19] *}

The first part of the function, before the `yield`, will be executed **before** the application starts.

And the part after the `yield` will be executed **after** the application has finished.

### Async Context Manager { #async-context-manager }

                } catch (InterruptedException e) {
                    log.debug("Async notification monitoring interrupted for {}", registrationId);
                    Thread.currentThread().interrupt();
                    break;
                } catch (Exception e) {
                    log.debug("Error in async notification monitoring for {}: {}", registrationId, e.getMessage());

///

##  `async` ⚖️ 🚫 `async`

🔗 🔜 🤙 **FastAPI** (🎏 👆 *➡ 🛠️ 🔢*), 🎏 🚫 ✔ ⏪ 🔬 👆 🔢.

👆 💪 ⚙️ `async def` ⚖️ 😐 `def`.

& 👆 💪 📣 🔗 ⏮️ `async def` 🔘 😐 `def` *➡ 🛠️ 🔢*, ⚖️ `def` 🔗 🔘 `async def` *➡ 🛠️ 🔢*, ♒️.

⚫️ 🚫 🤔. **FastAPI** 🔜 💭 ⚫️❔.

/// note

🚥 👆 🚫 💭, ✅ [🔁: *"🏃 ❓" *](../../async.md){.internal-link target=_blank} 📄 🔃 `async` & `await` 🩺.

    * This is especially useful if you run `await myfile.read()` once and then need to read the contents again.
* `close()`: Closes the file.

As all these methods are `async` methods, you need to "await" them.

For example, inside of an `async` *path operation function* you can get the contents with:

```Python
contents = await myfile.read()
```

## `async` oder nicht `async`

Da Abhängigkeiten auch von **FastAPI** aufgerufen werden (so wie Ihre *Pfadoperation-Funktionen*), gelten beim Definieren Ihrer Funktionen die gleichen Regeln.

Sie können `async def` oder einfach `def` verwenden.

import org.dbflute.mail.send.supplement.async.SMailAsyncStrategy;
import org.dbflute.mail.send.supplement.filter.SMailSubjectFilter;
import org.dbflute.mail.send.supplement.label.SMailLabelStrategy;
import org.dbflute.optional.OptionalThing;
import org.dbflute.util.DfStringUtil;
import org.lastaflute.core.magic.async.AsyncManager;
import org.lastaflute.core.magic.async.ConcurrentAsyncCall;

* `close()`: Закрыть файл.

Поскольку все эти методы являются `async` методами, вам следует использовать "await" вместе с ними.

Например, внутри `async` *функции операции пути* можно получить содержимое с помощью:

```Python
contents = await myfile.read()
```

8. Nota que esta *path operation function* usa `def` regular en lugar de `async def`.

    Como siempre, en FastAPI puedes combinar `def` y `async def` según sea necesario.

    Si necesitas un repaso sobre cuándo usar cuál, revisa la sección _"¿Con prisa?"_ en la documentación sobre [`async` y `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

8. Note que esta *função de operação de rota* usa `def` regular em vez de `async def`.

    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}.