import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Ticker;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

/**
 * A Ticker whose value can be advanced programmatically in test.
 *
 * <p>The ticker can be configured so that the time is incremented whenever {@link #read} is called:

  public void testAdvance() {
    FakeTicker ticker = new FakeTicker();
    assertEquals(0, ticker.read());
    assertSame(ticker, ticker.advance(10));
    assertEquals(10, ticker.read());
    ticker.advance(1, MILLISECONDS);
    assertEquals(1000010L, ticker.read());
    ticker.advance(Duration.ofMillis(1));
    assertEquals(2000010L, ticker.read());
  }

  public void testAutoIncrementStep_returnsSameInstance() {

  }

  public void testElapsed_notRunning() {
    ticker.advance(1);
    stopwatch.start();
    ticker.advance(4);
    stopwatch.stop();
    ticker.advance(9);
    assertEquals(4, stopwatch.elapsed(NANOSECONDS));
  }

  public void testElapsed_multipleSegments() {
    stopwatch.start();
    ticker.advance(9);
    stopwatch.stop();

    ticker.advance(16);

    stopwatch.start();

  }

  public void testElapsed_notRunning() {
    ticker.advance(1);
    stopwatch.start();
    ticker.advance(4);
    stopwatch.stop();
    ticker.advance(9);
    assertEquals(4, stopwatch.elapsed(NANOSECONDS));
  }

  public void testElapsed_multipleSegments() {
    stopwatch.start();
    ticker.advance(9);
    stopwatch.stop();

    ticker.advance(16);

    stopwatch.start();

   *
   * @since 15.0
   */
  public static Stopwatch createStarted(Ticker ticker) {
    return new Stopwatch(ticker).start();
  }

  Stopwatch() {
    this.ticker = Ticker.systemTicker();
  }

  Stopwatch(Ticker ticker) {
    this.ticker = checkNotNull(ticker, "ticker");
  }

  /**

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Ticker;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

/**
 * A Ticker whose value can be advanced programmatically in test.
 *
 * <p>The ticker can be configured so that the time is incremented whenever {@link #read} is called:

		},
		{
			val:   0.79,
			label: labels[2],
		},
	}
	ticker := time.NewTicker(1 * time.Millisecond)
	defer ticker.Stop()
	for _, obs := range observations {
		// Send observations once every 1ms, to simulate delay between
		// observations. This is to test the channel based
		// synchronization used internally.
		select {
		case <-ticker.C:
			ttfbHist.With(prometheus.Labels{"api": obs.label}).Observe(obs.val)
		}

    ticker.advance(1);
    segment.recordRead(entry, ticker.read());
    segment.expireEntries(ticker.read());
    assertTrue(map.containsKey(key));
    assertSame(entry, segment.accessQueue.peek());
    assertEquals(1, segment.accessQueue.size());

    ticker.advance(1);
    segment.recordRead(entry, ticker.read());
    segment.expireEntries(ticker.read());

    ticker.advance(1);
    segment.recordRead(entry, ticker.read());
    segment.expireEntries(ticker.read());
    assertTrue(map.containsKey(key));
    assertSame(entry, segment.accessQueue.peek());
    assertEquals(1, segment.accessQueue.size());

    ticker.advance(1);
    segment.recordRead(entry, ticker.read());
    segment.expireEntries(ticker.read());

  private static class Timestamped<V> {
    private final V value;
    private final Ticker ticker;
    private long writeTimestamp;
    private long accessTimestamp;

    public Timestamped(V value, Ticker ticker) {
      this.value = checkNotNull(value);
      this.ticker = checkNotNull(ticker);
      this.writeTimestamp = ticker.read();
      this.accessTimestamp = this.writeTimestamp;
    }