Dans cet exemple, la fonction de tâche écrira dans un fichier (afin de simuler un envoi d'email).

L'opération d'écriture n'utilisant ni `async` ni `await`, on définit la fonction avec un `def` normal.

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

## Ajouter une tâche d'arrière-plan

	wg := sync.WaitGroup{}
	wg.Add(1000)
	for i := 0; i < 1000; i++ {
		go func(i int) {
			lc.Add(fmt.Sprintf("key-%d", i/10), fmt.Sprintf("val-%d", i/10))
			wg.Done()
		}(i)
	}
	wg.Wait()
	if lc.Len() != 100 {
		t.Fatalf("length differs from expected")
	}
}

func TestLRUInvalidateAndEvict(t *testing.T) {
	var evicted int
	lc := lru.NewLRU(-1, func(_, _ string) { evicted++ }, 0)

			http.StatusOK, rec.Code, string(resp))
	}

	result := &serviceResult{}
	if err := json.Unmarshal(resp, result); err != nil {
		t.Error(err)
	}
	_ = result

	// Wait until testServiceSignalReceiver() called in a goroutine quits.
	wg.Wait()
}

// Test for service restart management REST API.
func TestServiceRestartHandler(t *testing.T) {
	testServicesCmdHandler(restartCmd, t)
}

## ✍ 📋 🔢

✍ 🔢 🏃 🖥 📋.

⚫️ 🐩 🔢 👈 💪 📨 🔢.

⚫️ 💪 `async def` ⚖️ 😐 `def` 🔢, **FastAPI** 🔜 💭 ❔ 🍵 ⚫️ ☑.

👉 💼, 📋 🔢 🔜 ✍ 📁 (⚖ 📨 📧).

& ✍ 🛠️ 🚫 ⚙️ `async` & `await`, 👥 🔬 🔢 ⏮️ 😐 `def`:

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

## 🚮 🖥 📋

🔘 👆 *➡ 🛠️ 🔢*, 🚶‍♀️ 👆 📋 🔢 *🖥 📋* 🎚 ⏮️ 👩‍🔬 `.add_task()`:

In diesem Fall schreibt die Taskfunktion in eine Datei (den Versand einer E-Mail simulierend).

Und da der Schreibvorgang nicht `async` und `await` verwendet, definieren wir die Funktion mit normalem `def`:

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

## Den Hintergrundtask hinzufügen

En este caso, la función de tarea escribirá en un archivo (simulando el envío de un email).

Y como la operación de escritura no usa `async` y `await`, definimos la función con un `def` normal:

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

## Agregar la tarea en segundo plano

      loader.reset();
      assertEquals(Integer.valueOf(VALUE_PREFIX + i), cache.getUnchecked(KEY_PREFIX + i));
      assertFalse("Loader should NOT have been called @#" + i, loader.wasCalled());
    }

    // wait for entries to expire, but don't call expireEntries
    ticker.advance(EXPIRING_TIME * 10, MILLISECONDS);

    // add a single unexpired entry
    cache.getUnchecked(KEY_PREFIX + 11);

					return
				}
			}

			// All versions resulted in 'ObjectNotFound/VersionNotFound'
			if versionNotFound == len(fivs.Versions) {
				return
			}

			send(healEntryDone(entry.name))

			// Wait and proceed if there are active requests
			waitForLowHTTPReq()
		}

		// How to resolve partial results.
		resolver := metadataResolutionParams{
			dirQuorum: 1,
			objQuorum: 1,
			bucket:    bucket,

			o.StopDiskAtLimit = true
		}
		listErr = z.listMerged(listCtx, o, filterCh)
		o.debugln("listMerged returned with", listErr)
	}(*o)

	entries, err = filteredResults()
	cancelList()
	wg.Wait()
	if listErr != nil && !errors.Is(listErr, context.Canceled) {
		return entries, listErr
	}
	entries.reuse = true
	truncated := entries.len() > o.Limit || err == nil
	entries.truncate(o.Limit)

	}

	// If we have too many waiting, reject this at once.
	if l.waitMutex.Load() > lockMutexWaitLimit {
		l.locksOverloaded.Add(1)
		return false, nil
	}
	// Wait for mutex
	defer l.getMutex()()
	if ctx.Err() != nil {
		return false, ctx.Err()
	}
	if !l.canTakeLock(args.Resources...) {
		// Not all locks can be taken on resources,
		// reject it completely.