e: IOException,
  )

  /**
   * Called when the HTTP response was successfully returned by the remote server. The callback may
   * proceed to read the response body with [Response.body]. The response is still live until its
   * response body is [closed][ResponseBody]. The recipient of the callback may consume the response
   * body on another thread.
   *

///

### Create a callback `APIRouter` { #create-a-callback-apirouter }

First create a new `APIRouter` that will contain one or more callbacks.

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[1,23] *}

### Create the callback *path operation* { #create-the-callback-path-operation }

To create the callback *path operation* use the same `APIRouter` you created above.

    boolean ran = false;
    @Nullable Callback callback = null;

    SimpleTearDown() {}

    SimpleTearDown(Callback callback) {
      this.callback = callback;
    }

    @Override
    public void tearDown() throws Exception {
      if (callback != null) {
        callback.run();
      }
      ran = true;
    }
  }

  private interface Callback {
    void run();
  }

            Consumer<RESPONSE> callback;
            while ((callback = doneCallbacks.poll()) != null) {
                executeCallbacks.add(callback);
            }
        }
        if (executeCallbacks.size() > 0) {
            try {
                executeCallbacks.stream().forEach(callback -> callback.accept(response));
            } catch (final Exception ignore) {}
        }

        loadIncludes(path, sp, callback);
        substitute(sp, callback);
        sp.forEach(properties::setProperty);
    }

    public static void substitute(MavenProperties props, UnaryOperator<String> callback) {
        for (Enumeration<?> e = props.propertyNames(); e.hasMoreElements(); ) {
            String name = (String) e.nextElement();

        interpolate(properties, callback, null, true);
    }

    /**
     * Interpolates the values in the given map using the provided callback function.
     *
     * @param map The map containing key-value pairs to be interpolated.
     * @param callback The function to resolve variable values not found in the map.

     * The callback is invoked for each chunk of the response.
     *
     * @param request the chat request containing messages and parameters
     * @param callback the callback to receive streaming chunks
     * @throws LlmException if an error occurs during the request
     */
    void streamChat(LlmChatRequest request, LlmStreamCallback callback);

    /**
     * Returns the name of this LLM client.

///

### 加入回呼 router { #add-the-callback-router }

此時你已經在先前建立的回呼 router 中，擁有所需的回呼「路徑操作（們）」（也就是「外部開發者」應該在「外部 API」中實作的那些）。

現在在「你的 API 的路徑操作裝飾器」中使用參數 `callbacks`，將該回呼 router 的屬性 `.routes`（實際上就是一個由路由／「路徑操作」所組成的 `list`）傳入：

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[33] *}

/// tip

    boolean ran = false;
    @Nullable Callback callback = null;

    SimpleTearDown() {}

    SimpleTearDown(Callback callback) {
      this.callback = callback;
    }

    @Override
    public void tearDown() throws Exception {
      if (callback != null) {
        callback.run();
      }
      ran = true;
    }
  }

  private interface Callback {
    void run();
  }

    MockCallback callback = new MockCallback("foo");
    addCallback(f, callback, directExecutor());
    f.set("foo");
  }

  public void testExecutorSuccess() {
    CountingSameThreadExecutor ex = new CountingSameThreadExecutor();
    SettableFuture<String> f = SettableFuture.create();
    MockCallback callback = new MockCallback("foo");
    Futures.addCallback(f, callback, ex);
    f.set("foo");