public @Nullable Void call() throws InterruptedException {
      running = true;
      startLatch.countDown();
      stopLatch.await();
      running = false;
      return null;
    }

    public void waitForStart() throws InterruptedException {
      startLatch.await();
    }

    public void stop() {
      stopLatch.countDown();
    }

    public boolean isRunning() {

	h.countScanned(healType)

	if source.noWait {
		select {
		case globalBackgroundHealRoutine.tasks <- task:
			if serverDebugLog {
				fmt.Printf("Task in the queue: %#v\n", task)
			}
		default:
			// task queue is full, no more workers, we shall move on and heal later.
			return nil
		}
		// Don't wait for result
		return nil
	}

	// respCh must be set to wait for result.

						// proceed to heal nonetheless, since
						// this object might be dangling.
						entry, _ = entries.firstFound()
					}
					wait := noWait
					if f.weSleep() {
						// wait timer per object.
						wait = scannerSleeper.Timer(ctx)
					}
					defer wait()
					f.updateCurrentPath(entry.name)
					stopFn := globalScannerMetrics.log(scannerMetricHealAbandonedObject, f.root, entry.name)

results = await some_library()
```
Alors, déclarez vos *fonctions de chemins* avec `async def` comme ceci :

```Python hl_lines="2"
@app.get('/')
async def read_results():
    results = await some_library()
    return results
```

/// note

Vous pouvez uniquement utiliser `await` dans les fonctions créées avec `async def`.

///

---

```Python
with open("file.txt") as file:
    file.read()
```

In recent versions of Python, there's also an **async context manager**. You would use it with `async with`:

```Python
async with lifespan(app):
    await do_stuff()
```

  //      */
  //     public void await(AtomicBoolean flag) {
  //         await(flag, LONG_DELAY_MS);
  //     }

  //     /**
  //      * Spin-waits up to the specified timeout until flag becomes true.
  //      */
  //     public void await(AtomicBoolean flag, long timeoutMillis) {
  //         long startTime = System.nanoTime();
  //         while (!flag.get()) {

  //      */
  //     public void await(AtomicBoolean flag) {
  //         await(flag, LONG_DELAY_MS);
  //     }

  //     /**
  //      * Spin-waits up to the specified timeout until flag becomes true.
  //      */
  //     public void await(AtomicBoolean flag, long timeoutMillis) {
  //         long startTime = System.nanoTime();
  //         while (!flag.get()) {

# Concurrencia y async / await

Detalles sobre la sintaxis `async def` para *path operation functions* y un poco de información sobre código asíncrono, concurrencia y paralelismo.

## ¿Tienes prisa?

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

Si estás utilizando libraries de terceros que te dicen que las llames con `await`, del tipo:

```Python
results = await some_library()
```

	interfaceTxBytes  MetricName = "tx_bytes"
	interfaceTxErrors MetricName = "tx_errors"

	// cpu stats
	cpuUser       MetricName = "user"
	cpuSystem     MetricName = "system"
	cpuIOWait     MetricName = "iowait"
	cpuIdle       MetricName = "idle"
	cpuNice       MetricName = "nice"
	cpuSteal      MetricName = "steal"
	cpuLoad1      MetricName = "load1"
	cpuLoad5      MetricName = "load5"
	cpuLoad15     MetricName = "load15"

      thread.start();
      // we want to wait until each thread is WAITING - one thread waiting inside CacheLoader.load
      // (in startSignal.await()), and the others waiting for that thread's result.
      while (thread.isAlive() && thread.getState() != Thread.State.WAITING) {
        Thread.yield();
      }
    }
    gettersStartedSignal.countDown();
    gettersComplete.await();