}
      return processor.getResult();
    }

    @Override
    public String toString() {
      return "CharSource.wrap(" + Ascii.truncate(seq, 30, "...") + ")";
    }
  }

  /**
   * Subclass specialized for string instances.
   *
   * <p>Since Strings are immutable and built into the jdk we can optimize some operations
   *
   * <ul>

이 간단한 경우는 반환 타입 어노테이션이 `Response` 클래스(또는 그 서브클래스)이기 때문에 FastAPI에서 자동으로 처리됩니다.

그리고 `RedirectResponse`와 `JSONResponse`는 모두 `Response`의 서브클래스이므로, 타입 어노테이션이 올바르기 때문에 도구들도 만족합니다.

### Response 서브클래스 어노테이션 { #annotate-a-response-subclass }

타입 어노테이션에 `Response`의 서브클래스를 사용할 수도 있습니다:

{* ../../docs_src/response_model/tutorial003_03_py310.py hl[8:9] *}

이는 `RedirectResponse`가 `Response`의 서브클래스이기 때문에 동작하며, FastAPI가 이 간단한 경우를 자동으로 처리합니다.

    /*
     * requireNonNull is not safe: Joiner.on(...).join(somethingThatContainsNull) will indeed throw.
     * However, Joiner.on(...).useForNull(...).join(somethingThatContainsNull) *is* safe -- because
     * it returns a subclass of Joiner that overrides this method to tolerate null inputs.
     *
     * Unfortunately, we don't distinguish between these two cases in our public API: Joiner.on(...)

Y las herramientas también estarán felices porque tanto `RedirectResponse` como `JSONResponse` son subclases de `Response`, por lo que la anotación del tipo es correcta.

### Anotar una Subclase de Response { #annotate-a-response-subclass }

También puedes usar una subclase de `Response` en la anotación del tipo:

{* ../../docs_src/response_model/tutorial003_03_py310.py hl[8:9] *}

   * Returns a serializable form of this object. Non-public subclasses should not override this
   * method. Publicly-accessible subclasses must override this method and should return a subclass
   * of SerializedForm whose readResolve() method returns objects of the subclass type.
   */
  @J2ktIncompatible // serialization
  Object writeReplace() {
    return new SerializedForm<>(this);
  }

Et les outils seront également satisfaits car `RedirectResponse` et `JSONResponse` sont des sous-classes de `Response`, donc l'annotation de type est correcte.

### Annoter une sous-classe de Response { #annotate-a-response-subclass }

Vous pouvez aussi utiliser une sous-classe de `Response` dans l'annotation de type :

{* ../../docs_src/response_model/tutorial003_03_py310.py hl[8:9] *}

       * more information, see the comments in that class.
       *
       * We already know that that's how it behaves, and subclasses of Converter can't change that
       * behavior. So there's no sense in making all subclass authors exclude the method from any
       * NullPointerTester tests that they have.
       */
      ignoredMembers.add(Converter.class.getMethod("apply", Object.class));
    } catch (NoSuchMethodException shouldBeImpossible) {

        final List<Map<String, Object>> result = chatClient.testSearchWithQuery("nonexistent");
        assertTrue(result.isEmpty());
    }

    // ========== Testable subclass ==========

    static class TestableChatClient extends ChatClient {

        private boolean searchDocumentsCalled = false;
        private final List<String> searchedQueries = new ArrayList<>();

                + "\"instanceId\":\"node1@host1\",\"status\":\"running\"," + "\"expiredTime\":" + (now + 3600000L) + "}}";
        final CurlResponse mockResponse = createMockResponse(200, opJson);

        // Use a subclass to mock both CurlHelper access and getActiveInstances
        final CoordinatorHelper helper = new CoordinatorHelper() {
            @Override
            public List<InstanceInfo> getActiveInstances() {

    }

    @Override
    public void forEach(Consumer<? super T> action) {
      iterable.forEach(action);
    }

    @SuppressWarnings("unchecked") // safe upcast, assuming no one has a crazy Spliterator subclass
    @Override
    public Spliterator<T> spliterator() {
      return (Spliterator<T>) iterable.spliterator();
    }

    @Override
    public String toString() {
      return iterable.toString();