```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.

<a href="#Switch_statements">"switch"</a> statements,
they can be used to declare local temporary variables.
</p>

<h3 id="Function_declarations">Function declarations</h3>

<!--
	Given the importance of functions, this section has always
	been woefully underdeveloped. Would be nice to expand this
	a bit.
-->

<p>
A function declaration binds an identifier, the <i>function name</i>,
to a function.

Entonces, para evitar colisiones de ID, cuando crees el token JWT para el usuario, podrías prefijar el valor de la clave `sub`, por ejemplo, con `username:`. Así, en este ejemplo, el valor de `sub` podría haber sido: `username:johndoe`.

Lo importante a tener en cuenta es que la clave `sub` debería tener un identificador único a lo largo de toda la aplicación, y debería ser un string.

## Revisa

/**
 * This class will allow a Java program to read and write data to Named
 * Pipes and Transact NamedPipes.
 *
 * <p>
 * There are three Win32 function calls provided by the Windows SDK
 * that are important in the context of using jCIFS. They are:
 *
 * <ul>
 * <li><code>CallNamedPipe</code> A message-type pipe call that opens,
 * writes to, reads from, and closes the pipe in a single operation.

       * timeoutFuture.setException() calls run(). That reentrancy would already be harmless, since
       * timeoutFuture can be set (and delegate cancelled) only once. (And "set only once" is
       * important for other reasons: run() can still be invoked concurrently in different threads,
       * even with the above null checks.)
       */
      timeoutFutureRef = null;
      if (delegate.isDone()) {

Pero primero, vamos a revisar algunos pequeños conceptos.

## ¿Con prisa?

Si no te importan ninguno de estos términos y solo necesitas agregar seguridad con autenticación basada en nombre de usuario y contraseña *ahora mismo*, salta a los siguientes capítulos.

## OAuth2

    Como esto contiene todo el código, que es lo que **cambia con más frecuencia**, la **caché de Docker** no se utilizará para este u otros **pasos siguientes** fácilmente.

    Así que es importante poner esto **cerca del final** del `Dockerfile`, para optimizar los tiempos de construcción de la imagen del contenedor.

6. Establecer el **comando** para usar `fastapi run`, que utiliza Uvicorn debajo.

	// Verify if region is valid.
	sRegion := cred.scope.region
	// Region is set to be empty, we use whatever was sent by the
	// request and proceed further. This is a work-around to address
	// an important problem for ListBuckets() getting signed with
	// different regions.
	if region == "" {
		region = sRegion
	}
	// Should validate region, only if region is set.
	if !isValidRegion(sRegion, region) {

        });
    }

    @Test
    @DisplayName("Should maintain serialization compatibility")
    void testSerialization() {
        // Verify the class has serialVersionUID defined
        // This is important for version compatibility
        RuntimeCIFSException exception = new RuntimeCIFSException("Test");

        // The class should be serializable as it extends RuntimeException

import java.io.Serializable;
import java.util.Map;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * A {@link ClassToInstanceMap} whose contents will never change, with many other important
 * properties detailed at {@link ImmutableCollection}.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@Immutable(containerOf = "B")
@GwtIncompatible