fromSink.writeByte(VERSION_5)
        fromSink.writeByte(selectedMethod)
        fromSink.emit()
      }

      else -> {
        throw ProtocolException("unsupported method: $selectedMethod")
      }
    }
  }

  private fun acceptCommand(
    fromAddress: InetAddress,
    fromSource: BufferedSource,
    fromSink: BufferedSink,
  ) {
    // Read the command.

    }

    /**
     * Filter out whitelisted projects with a big twist:
     * Assume we have all projects {@code a, b, c} while active are {@code a, c} and relation among all projects
     * is {@code a -> b -> c}. This method handles well the case for transitive list. But, for non-transitive we need
     * to "pull in" transitive dependencies of eliminated projects, as for case above, the properly filtered list would
     * be {@code a -> c}.

* model
* Pydantic model
* data model
* database model
* form model
* model object

* class
* base class
* parent class
* subclass
* child class
* sibling class
* class method

* header
* headers
* authorization header
* `Authorization` header
* forwarded header

* dependency injection system
* dependency
* dependable
* dependant

* I/O bound

若你為使用標籤的 FastAPI 應用產生用戶端，產生器通常也會依標籤將用戶端程式碼分開。

如此一來，用戶端程式碼就能有條理地正確分組與排列：

<img src="/img/tutorial/generate-clients/image06.png">

在此例中，你會有：

* `ItemsService`
* `UsersService`

### 用戶端方法名稱 { #client-method-names }

目前像 `createItemItemsPost` 這樣的產生方法名稱看起來不太俐落：

```TypeScript
ItemsService.createItemItemsPost({name: "Plumbus", price: 5})
```

...那是因為用戶端產生器對每個 *路徑操作* 都使用 OpenAPI 內部的**操作 ID（operation ID）**。

    assertThat(call1Connect.method).isEqualTo("CONNECT")
    assertThat(call1Connect.exchangeIndex).isEqualTo(0)
    val call2Connect = server.takeRequest()
    assertThat(call2Connect.method).isEqualTo("CONNECT")
    assertThat(call2Connect.exchangeIndex).isEqualTo(0)
    val call2Get = server.takeRequest()
    assertThat(call2Get.method).isEqualTo("GET")

        requestCounters.cleanUp();
        return (int) requestCounters.size();
    }

    /**
     * Clean up expired entries.
     * Note: Guava Cache handles expiration automatically, but this method
     * can be called to force immediate cleanup.
     */
    public void cleanup() {
        requestCounters.cleanUp();
        blockedIps.cleanUp();
        if (logger.isDebugEnabled()) {

   * try (Response response = client.newCall(request).execute()) {
   *   ...
   * }
   * ```
   *
   * The caller may read the response body with the response's [Response.body] method. To avoid
   * leaking resources callers must [close the response body][ResponseBody] or the response.
   *
   * Note that transport-layer success (receiving a HTTP response code, headers and body) does not

    Thread.sleep(100)
    for (t in taskRunnerThreads) {
      t.interrupt()
    }
    Thread.sleep(100)
    assertThat(taskRunner.activeQueues()).isEmpty()
  }

  /** Use a helper method so there's no hidden reference remaining on the stack.  */
  private fun allocateAndLeakAllocation(
    pool: ConnectionPool,
    connection: RealConnection,
  ) {
    val client =
      OkHttpClient

* `expose_headers` - 指示可以被浏览器访问的响应头。默认为 `[]`。
* `max_age` - 设定浏览器缓存 CORS 响应的最长时间，单位是秒。默认为 `600`。

中间件响应两种特定类型的 HTTP 请求...

### CORS 预检请求 { #cors-preflight-requests }

这是些带有 `Origin` 和 `Access-Control-Request-Method` 请求头的 `OPTIONS` 请求。

在这种情况下，中间件将拦截传入的请求并进行响应，出于提供信息的目的返回一个使用了适当的 CORS headers 的 `200` 或 `400` 响应。

### 简单请求 { #simple-requests }

任何带有 `Origin` 请求头的请求。在这种情况下，中间件将像平常一样传递请求，但是在响应中包含适当的 CORS headers。

      }
    }
  }

  /** Helper method that asserts the arithmetic mean of x and y is equal to the expectedMean. */
  private static void assertMean(int expectedMean, int x, int y) {
    assertEquals(
        "The expectedMean should be the same as computeMeanSafely",
        expectedMean,
        computeMeanSafely(x, y));
    assertMean(x, y);
  }

  /**