* <ul>
 * <li>os.name: The operating system name</li>
 * <li>os.arch: The operating system architecture</li>
 * <li>os.version: The operating system version</li>
 * </ul>
 * <p>
 * Supported OS families include:
 * <ul>
 * <li>windows: All Windows variants</li>
 * <li>win9x: Windows 95, 98, ME, CE</li>
 * <li>winnt: Windows NT variants</li>
 * <li>unix: Unix-like systems (including Linux)</li>

With fast fallback, OkHttp attempts to connect to multiple web servers concurrently. It keeps whichever route connects first and cancels all of the others. Its rules are:

 * Prefer to alternate IP addresses from different address families, (IPv6 / IPv4), starting with IPv6.
 * Don't start a new attempt until 250 ms after the most recent attempt was started.
 * Keep whichever TCP connection succeeds first and cancel all the others.

- Kubenet: added HostPort IPv6 support.  HostPortManager: operates only with one IP family, failing if receives port mapping entries with different IP families.  HostPortSyncer: operates only with one IP family, skipping portmap entries with different IP families ([#80854](https://github.com/kubernetes/kubernetes/pull/80854), [@aojea](https://github.com/aojea))

  It changes the dual-stack API wrt Service from a single ipFamily field to 3
  fields: ipFamilyPolicy (SingleStack, PreferDualStack, RequireDualStack),
  ipFamilies (a list of families assigned), and clusterIPs (inclusive of
  clusterIP).  Most users do not need to set anything at all, defaulting will
  handle it for them.  Services are single-stack unless the user asks for

- The `--bind-address` parameter in kube-proxy is misleading, no port is opened with this address. Instead it is translated internally to "nodeIP". The nodeIPs for both families are now taken from the Node object if `--bind-address` is unspecified or set to the "any" address (0.0.0.0 or ::). It is recommended to leave `--bind-address` unspecified, and in particular avoid to set it to localhost (127.0.0.1 or ::1) ([#1195...

- Kube-proxy will now warn at startup if the configuration seems inconsistent
  with respect to IP families. (For example, if you have an IPv4 node IP, but
  `--cluster-cidr` is IPv6.) ([#119003](https://github.com/kubernetes/kubernetes/pull/119003), [@danwinship](https://github.com/danwinship)) [SIG Network]

Ele é baseado no <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, que por sua vez é projetado com base em Requests, por isso é muito familiar e intuitivo.

Com ele, você pode usar o <a href="https://docs.pytest.org/" class="external-link" target="_blank">pytest</a> diretamente com **FastAPI**.

## Usando `TestClient`

/// info | Informação

@app.get("/items/{item_id}")
async def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

**Note**

Si vous n'êtes pas familier avec cette notion, consultez la section _"Vous êtes pressés ?"_ à propos de <a href="https://fastapi.tiangolo.com/fr/async/#vous-etes-presses" target="_blank">`async` et `await` dans la documentation</a>.

</details>

Está basado en <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, que a su vez está diseñado basado en Requests, por lo que es muy familiar e intuitivo.

Con él, puedes usar <a href="https://docs.pytest.org/" class="external-link" target="_blank">pytest</a> directamente con **FastAPI**.

## Usando `TestClient`

/// info | Información

It is based on <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, which in turn is designed based on Requests, so it's very familiar and intuitive.

With it, you can use <a href="https://docs.pytest.org/" class="external-link" target="_blank">pytest</a> directly with **FastAPI**.

## Using `TestClient` { #using-testclient }

/// info