afterStarted.countDown();
    // We do not call awaitHealthy because, due to races, that method may throw an exception.  But
    // we really just want to wait for the thread to be in the failure callback so we wait for that
    // explicitly instead.
    failEnter.await();
    assertFalse("State should be updated before calling listeners", manager.isHealthy());
    // now we want to stop the services.
    Thread stoppingThread =

Nesse caso, a função de tarefa gravará em um arquivo (simulando o envio de um e-mail).

E como a operação de gravação não usa `async` e `await`, definimos a função com `def` normal:

```Python hl_lines="6-9"
{!../../docs_src/background_tasks/tutorial001.py!}
```

## Adicionar a tarefa em segundo plano

In this case, the task function will write to a file (simulating sending an email).

And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Add the background task

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>⚖️ ⚙️ <code>async def</code>...</summary>

🚥 👆 📟 ⚙️ `async` / `await`, ⚙️ `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>או השתמשו ב - <code>async def</code>...</summary>

אם הקוד שלכם משתמש ב - `async` / `await`, השתמשו ב - `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

                logger.error("Failed to update suggest index.", t);
                exitCode.set(1);
                latch.countDown();
            });

            try {
                latch.await();
            } catch (final InterruptedException ignore) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Interrupted.", ignore);
                }
                exitCode.set(1);

    }

    val startedTask = startNextTask()
    val otherTasksStarted = startedTask != yieldCompleteTask

    try {
      while (currentTask != self) {
        taskRunner.condition.await()
      }
    } finally {
      serialTaskQueue.remove(yieldCompleteTask)
    }

    // If we're yielding until we're exhausted and a task run, keep going until a task doesn't run.

        new UncaughtExceptionHandler() {
          @Override
          public void uncaughtException(Thread t, Throwable e) {}
        });
    thread.start();

    boolean done = doneSignal.await(1, SECONDS);
    if (!done) {
      StringBuilder builder = new StringBuilder();
      for (StackTraceElement trace : thread.getStackTrace()) {
        builder.append("\tat ").append(trace).append('\n');
      }

        new UncaughtExceptionHandler() {
          @Override
          public void uncaughtException(Thread t, Throwable e) {}
        });
    thread.start();

    boolean done = doneSignal.await(1, SECONDS);
    if (!done) {
      StringBuilder builder = new StringBuilder();
      for (StackTraceElement trace : thread.getStackTrace()) {
        builder.append("\tat ").append(trace).append('\n');
      }

        )

    tasks.add_task(bg, state)
    return state


@app.middleware("http")
async def middleware(request, call_next):
    response: StreamingResponse = await call_next(request)
    response.headers["x-state"] = json.dumps(state.copy())
    return response


client = TestClient(app)


def test_async_state():