Using a relative URL is important to make sure your application keeps working even in an advanced use case like [Behind a Proxy](../../advanced/behind-a-proxy.md).

///

Comme ce code est exécuté avant que l'application ne **commence** à recevoir des requêtes, et juste après qu'elle **termine** de les traiter, il couvre tout le **cycle de vie** de l'application (le mot « lifespan » va être important dans un instant 😉).

Utiliser une URL relative est important pour vous assurer que votre application continue de fonctionner même dans un cas d'usage avancé comme [Derrière un proxy](../../advanced/behind-a-proxy.md).

///

Como este pequeño ejemplo no necesita ninguna sentencia `await`, añadimos un `await anyio.sleep(0)` para darle al loop de eventos la oportunidad de manejar la cancelación.

Esto sería aún más importante con streams grandes o infinitos.

///

/// tip | Consejo

We highly recommend you keep OkHttp up-to-date. As with auto-updating web browsers, staying current
with HTTPS clients is an important defense against potential security problems. [We
track][tls_history] the dynamic TLS ecosystem and adjust OkHttp to improve connectivity and
security.

 * inputs' {@link Comparable#compareTo compareTo} and {@link Comparator#compare compare} methods as
 * soon as one of them returns a nonzero result. This optimization is typically important only in
 * the presence of expensive {@code compareTo} and {@code compare} implementations.
 *
 * <p>See the Guava User Guide article on <a href=

```Python
callback_url = "https://example.com/api/v1/invoices/events/"
httpx.post(callback_url, json={"description": "Invoice paid", "paid": True})
```

But possibly the most important part of the callback is making sure that your API user (the external developer) implements the *external API* correctly, according to the data that *your API* is going to send in the request body of the callback, etc.

The client does not wait for the remote handler to finish before returning.
Returning any error will also cancel the stream remotely.

CAREFUL: When utilizing two-way communication, it is important to ensure that the remote handler is not blocked on a send.
If the remote handler is blocked on a send, and the client is trying to send without the remote receiving,
the operation would become deadlocked if the channels are full.

Algunos de los conceptos importantes son:

* Seguridad - HTTPS
* Ejecución al iniciar
* Reinicios
* Replicación (la cantidad de procesos en ejecución)
* Memoria
* Pasos previos antes de iniciar

Veremos cómo afectan estas **implementaciones**.

Então, para evitar colisões de ID, ao criar o token JWT para o usuário, você poderia prefixar o valor da chave `sub`, por exemplo, com `username:`. Assim, neste exemplo, o valor de `sub` poderia ser: `username:johndoe`.

O importante a se lembrar é que a chave `sub` deve ter um identificador único em toda a aplicação e deve ser uma string.

## Verifique { #check-it }