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

            settingsBuilder.put("http.cors.enabled", true);
            settingsBuilder.put("discovery.type", "single-node");
        }).build(newConfigs().clusterName(clusterName).numOfNode(1));

        // wait for yellow status
        runner.ensureYellow();

        System.setProperty(FesenClient.HTTP_ADDRESS, "localhost:" + runner.node().settings().get("http.port", "9201"));

        super.setUp();
    }

    @Override

            super.process(consumer);
            latch.countDown();
        }

        @Override
        public void waitForProcessed() throws InterruptedException {
            latch.await();
        }
    }

@REM
@REM Optional ENV vars
@REM M2_HOME - location of maven2's installed home dir
@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a keystroke before ending
@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
@REM     e.g. to debug Maven itself, use
@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000

	// Alert upon this many excess object versions
	ExcessVersions int64 // 100

	// Alert upon this many excess sub-folders per folder in an erasure set.
	ExcessFolders int64 // 50000

	// MaxWait is maximum wait time between operations
	MaxWait time.Duration
	// Cycle is the time.Duration between each scanner cycles
	Cycle time.Duration
}

// DefaultKVS - default KV config for heal settings
var DefaultKVS = config.KVS{

    }

    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():

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"}