func (s *Singleton[T]) IsSet() bool {
	select {
	case <-s.set:
		return true
	default:
		return false
	}
}

// Set the value and unblock all Get requests.
// This may only be called once, a second call will panic.
func (s *Singleton[T]) Set(v *T) {
	s.v = v
	close(s.set)

Existem várias maneiras para fazer isso, dependendo do seu caso específico e das ferramentas que você utiliza.

		return false, err
	}
	return target.isActive()
}

func (target *ElasticsearchTarget) isActive() (bool, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	err := target.checkAndInitClient(ctx)
	if err != nil {
		return false, err
	}

	return target.client.ping(ctx, target.args)
}

	}, []string{"tier"}),
}

func (t *tierMetrics) Observe(tier string, dur time.Duration) {
	t.histogram.With(prometheus.Labels{"tier": tier}).Observe(dur.Seconds())
}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++
	t.requestsCount[tier] = stat
}

# Aprender

Nesta parte da documentação encontramos as seções introdutórias e os tutoriais para aprendermos como usar o **FastAPI**.

@GwtCompatible(emulated = true)
public class AbstractIteratorTest extends TestCase {

  public void testDefaultBehaviorOfNextAndHasNext() {

    // This sample AbstractIterator returns 0 on the first call, 1 on the
    // second, then signals that it's reached the end of the data
    Iterator<Integer> iter =
        new AbstractIterator<Integer>() {
          private int rep;

          @Override
          public Integer computeNext() {

import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
import static java.util.concurrent.Executors.newScheduledThreadPool;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
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permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.