@J2ktIncompatible // Incompatible return type change. Use inherited implementation
  public Object[] toArray() {
    /*
     * If we could, we'd declare the no-arg `Collection.toArray()` to return "Object[] but elements
     * have the same nullness as E." Since we can't, we declare it to return nullable elements, and
     * we can override it in our non-null-guaranteeing subtypes to present a better signature to
     * their users.
     *

O la dependencia no devuelve un valor.

Pero aún necesitas que sea ejecutada/resuelta.

Para esos casos, en lugar de declarar un parámetro de *path operation function* con `Depends`, puedes añadir una `list` de `dependencies` al decorador de *path operation*.

To use, first add this library as a test dependency:

```
testImplementation("com.squareup.okhttp3:mockwebserver3-junit4:5.3.0")
```

Then in tests annotated `@org.junit.Test`, you may declare a field with the `@Rule` annotation:

```
@Rule public final MockWebServerRule serverRule = new MockWebServerRule();
```

The `serverRule` field has a `server` field. It is an instance of `MockWebServer`. That instance

Ou a dependência não retorna nenhum valor.

Mas você ainda precisa que ela seja executada/resolvida.

Para esses casos, em vez de declarar um parâmetro em uma *função de operação de rota* com `Depends`, você pode adicionar um argumento `dependencies` do tipo `list` ao decorador da operação de rota.

  public void testNulls() {
    try {
      Class.forName("java.lang.reflect.AnnotatedType");
    } catch (ClassNotFoundException runningInAndroidVm) {
      /*
       * Parameter declares a method that returns AnnotatedType, which isn't available on Android.
       * This would cause NullPointerTester, which calls Class.getDeclaredMethods, to throw
       * NoClassDefFoundError.
       */
      return;
    }

  public void testNulls() {
    try {
      Class.forName("java.lang.reflect.AnnotatedType");
    } catch (ClassNotFoundException runningInAndroidVm) {
      /*
       * Parameter declares a method that returns AnnotatedType, which isn't available on Android.
       * This would cause NullPointerTester, which calls Class.getDeclaredMethods, to throw
       * NoClassDefFoundError.
       */
      return;
    }

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[1:25] hl[4,22] *}

Chaque élément produit avec `yield` est encodé en JSON et envoyé dans le champ `data:` d’un événement SSE.

Si vous déclarez le type de retour comme `AsyncIterable[Item]`, FastAPI l’utilisera pour **valider**, **documenter** et **sérialiser** les données avec Pydantic.

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[1:25] hl[10:12,23] *}

# Headers de Response { #response-headers }

## Usa un parámetro `Response` { #use-a-response-parameter }

Puedes declarar un parámetro de tipo `Response` en tu *path operation function* (como puedes hacer para cookies).

Y luego puedes establecer headers en ese objeto de response *temporal*.

{* ../../docs_src/response_headers/tutorial002_py310.py hl[1, 7:8] *}

#dependencies-for-groups-of-path-operations }

Later, when reading about how to structure bigger applications ([Bigger Applications - Multiple Files](../../tutorial/bigger-applications.md)), possibly with multiple files, you will learn how to declare a single `dependencies` parameter for a group of *path operations*....

Se você declarar um [Modelo de resposta](../tutorial/response-model.md), o FastAPI irá usá-lo para serializar os dados para JSON, usando o Pydantic.