recoveredFailures += e
          newRoutePlanner = false
          continue
        }

        // Clear out downstream interceptor's additional request headers, cookies, etc.
        response =
          response
            .newBuilder()
            .request(request)
            .priorResponse(priorResponse?.stripBody())
            .build()

import java.util.concurrent.TimeUnit

/**
 * Observes, modifies, and potentially short-circuits requests going out and the corresponding
 * responses coming back in. Typically interceptors add, remove, or transform headers on the request
 * or response.
 *
 * Implementations of this interface throw [IOException] to signal connectivity failures. This
 * includes both natural exceptions such as unreachable servers, as well as synthetic exceptions

@app.get("/", dependencies=[Depends(bearer_scheme)])
async def get_root():
    return {"message": "Hello, World!"}


client = TestClient(app)


def test_get_root():
    response = client.get("/", headers={"Authorization": "Bearer token"})
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "Hello, World!"}


def test_get_root_no_token():
    response = client.get("/")

Cache Miss will be typical if the item has not been read from the network, is uncacheable, or is past it's 
lifetime based on Response cache headers.

 - CallStart 
 - **CacheMiss**
 - ProxySelectStart
 - ... Standard Events ...
 - CallEnd
        
### Conditional Cache Hit
 

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## Как запретить дополнительные заголовки { #forbid-extra-headers }

В некоторых случаях (не особо часто встречающихся) вам может понадобиться **ограничить** заголовки, которые вы хотите получать.

   * and `:path`.
   */
  fun onRequest(
    streamId: Int,
    requestHeaders: List<Header>,
  ): Boolean

  /**
   * The response headers corresponding to a pushed request.  When [last] is true, there are
   * no data frames to follow.
   *
   * @param streamId server-initiated stream ID: an even number.
   * @param responseHeaders minimally includes `:status`.

/// warning | Achtung

Bevor Sie `convert_underscores` auf `False` setzen, bedenken Sie, dass manche HTTP-Proxys und Server die Verwendung von Headern mit Unterstrichen nicht erlauben.

///

## Doppelte Header { #duplicate-headers }

Es ist möglich, doppelte Header zu empfangen. Damit ist gemeint, denselben Header mit mehreren Werten.

Sie können solche Fälle definieren, indem Sie in der Typdeklaration eine Liste verwenden.

async def read_admin():
    return {"message": "Admin Access"}


client = TestClient(app)


def test_read_admin():
    response = client.get("/admin", headers={"Authorization": "Bearer faketoken"})
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "Admin Access"}


def test_openapi_schema():

    assert response.json() == {"item": "The Foo Wrestlers"}


def test_get_item_not_found():
    response = client.get("/items/bar")
    assert response.status_code == 404, response.text
    assert response.headers.get("x-error") is None
    assert response.json() == {"detail": "Item not found"}


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

///

### `Response`

其他全部的响应都继承自主类 `Response`。

你可以直接返回它。

`Response` 类接受如下参数：

* `content` - 一个 `str` 或者 `bytes`。
* `status_code` - 一个 `int` 类型的 HTTP 状态码。
* `headers` - 一个由字符串组成的 `dict`。
* `media_type` - 一个给出媒体类型的 `str`，比如 `"text/html"`。

FastAPI（实际上是 Starlette）将自动包含 Content-Length 的头。它还将包含一个基于 media_type 的 Content-Type 头，并为文本类型附加一个字符集。