Y luego otra tarea en segundo plano generada en la *path operation function* escribirá un mensaje usando el parámetro de path `email`.

## Detalles Técnicos { #technical-details }

La clase `BackgroundTasks` proviene directamente de <a href="https://www.starlette.dev/background/" class="external-link" target="_blank">`starlette.background`</a>.

## OpenAPI Extra { #openapi-extra }

When you declare a *path operation* in your application, **FastAPI** automatically generates the relevant metadata about that *path operation* to be included in the OpenAPI schema.

/// note | Technical details

In the OpenAPI specification it is called the <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#operation-object" class="external-link" target="_blank">Operation Object</a>.

///

Поэтому теперь рекомендуется использовать `lifespan`, как описано выше.

## Технические детали { #technical-details }

Немного технических подробностей для любопытных умников. 🤓

Wenn Sie jedoch den oben genannten Schritten folgen, können einige Performanz-Optimierungen vorgenommen werden.

## Technische Details { #technical-details }

Moderne Versionen von Python unterstützen **„asynchronen Code“** unter Verwendung sogenannter **„Coroutinen“** mithilfe der Syntax **`async` und `await`**.

For more info about <abbr title="Cross-Origin Resource Sharing">CORS</abbr>, check the <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">Mozilla CORS documentation</a>.

/// note | Technical Details

You could also use `from starlette.middleware.cors import CORSMiddleware`.

Com `openapi_examples` adicionado a `Body()`, o `/docs` ficaria assim:

<img src="/img/tutorial/body-fields/image02.png">

## Detalhes Técnicos { #technical-details }

/// tip | Dica

Se você já está usando o **FastAPI** na versão **0.99.0 ou superior**, você provavelmente pode **pular** esses detalhes.

Con `openapi_examples` añadido a `Body()`, los `/docs` se verían así:

<img src="/img/tutorial/body-fields/image02.png">

## Detalles Técnicos { #technical-details }

/// tip | Consejo

Si ya estás usando la versión **0.99.0 o superior** de **FastAPI**, probablemente puedes **omitir** estos detalles.

And the calls to the client are also normal calls, not using `await`.

This allows you to use `pytest` directly without complications.

///

/// note | Technical Details

You could also use `from starlette.testclient import TestClient`.

**FastAPI** will know that it can use this dependency to define a "security scheme" in the OpenAPI schema (and the automatic API docs).

/// info | Technical Details

This simplicity and flexibility allow doing things like using NoSQL databases as the main data storage system.

As it is very simple, it's relatively intuitive to learn, although the documentation gets somewhat technical at some points.