*
   * If [routes] is non-null these are the resolved routes (ie. IP addresses) for the connection.
   * This is used to coalesce related domains to the same HTTP/2 connection, such as `square.com`
   * and `square.ca`.
   */
  internal fun callAcquirePooledConnection(
    doExtensiveHealthChecks: Boolean,
    address: Address,
    call: RealCall,
    routes: List<Route>?,
    requireMultiplexed: Boolean,

    """
    Simplify operation IDs so that generated API clients have simpler function
    names.

    Should be called only after all routes have been added.
    """
    for route in app.routes:
        if isinstance(route, APIRoute):
            route.operation_id = route.name  # in this case, 'read_items'

)
router_b_override.include_router(router_b_a, prefix="/a")
router_a.include_router(router_a_a, prefix="/a")
router_a.include_router(
    router_a_b_override, prefix="/b", default_response_class=PlainTextResponse
)
app.include_router(router_a, prefix="/a")
app.include_router(
    router_b_override, prefix="/b", default_response_class=PlainTextResponse
)

* `summary`: Краткое описание API.
* `description`: Описание вашего API; может включать Markdown и будет отображается в документации.
* `routes`: Список маршрутов — это каждая зарегистрированная *операция пути*. Берутся из `app.routes`.

/// info | Информация

Параметр `summary` доступен в OpenAPI 3.1.0 и выше, поддерживается FastAPI версии 0.99.0 и выше.

///

    router_b_a_c_override, prefix="/c", default_response_class=HTMLResponse
)
router_b_override.include_router(router_b_a, prefix="/a")
router_a.include_router(router_a_a, prefix="/a")
router_a.include_router(
    router_a_b_override, prefix="/b", default_response_class=PlainTextResponse
)
app.include_router(router_a, prefix="/a")
app.include_router(
    router_b_override, prefix="/b", default_response_class=PlainTextResponse
)

* path operation: operação de rota
* path operation function: função de operação de rota
* prefix: prefixo
* request (as in HTTP request): request (do not change if it's already translated to requisição)
* router (as in FastAPI's router): router (do not change if it's already translated to "roteador" or "roteadores")
* response (as in HTTP response): response (do not change if it's already translated to resposta)
* shutdown (of the app): encerramento

     *
     * @return true if the problem collector has overflowed and some problems were not preserved
     */
    boolean problemsOverflow();

    /**
     * Reports a problem: always maintains the counters, but whether problem is preserved in memory, depends on
     * implementation and its configuration.
     *
     * @param problem the problem to report
     * @return {@code true} if passed problem is preserved by this call.

### 添加回调路由

至此，在上文创建的回调路由里就包含了*回调路径操作*（外部开发者要在外部 API 中实现）。

现在使用 API *路径操作装饰器*的参数 `callbacks`，从回调路由传递属性 `.routes`（实际上只是路由/路径操作的**列表**）：

{* ../../docs_src/openapi_callbacks/tutorial001.py hl[36] *}

/// tip | 提示

注意，不能把路由本身（`invoices_callback_router`）传递给 `callback=`，要传递 `invoices_callback_router.routes` 中的 `.routes` 属性。

///

### 查看文档

In OkHttp some fields of the address come from the URL (scheme, hostname, port) and the rest come from the [OkHttpClient](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-ok-http-client/).

### [Routes](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-route/)

    "{$callback_url}/invoices/{$request.body.id}", response_model=InvoiceEventReceived
)
def invoice_notification(body: InvoiceEvent):
    pass


@app.post("/invoices/", callbacks=invoices_callback_router.routes)
def create_invoice(invoice: Invoice, callback_url: HttpUrl | None = None):
    """
    Create an invoice.

    This will (let's imagine) let the API user (some external developer) create an
    invoice.