for (int i = 0; i < 8; i++) {
      limiter.acquire(); // // #1
    }
    stopwatch.sleepMillis(4500); // #2: back to cold state (warmup period + repay last acquire)
    for (int i = 0; i < 3; i++) { // only three steps, we're somewhere in the warmup period
      limiter.acquire(); // #3
    }

    limiter.setRate(4.0); // double the rate!

   * second" (commonly referred to as <i>QPS</i>, queries per second), and a <i>warmup period</i>,
   * during which the {@code RateLimiter} smoothly ramps up its rate, until it reaches its maximum
   * rate at the end of the period (as long as there are enough requests to saturate it). Similarly,
   * if the {@code RateLimiter} is left <i>unused</i> for a duration of {@code warmupPeriod}, it

    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // // #1
    }
    stopwatch.sleepMillis(4500); // #2: back to cold state (warmup period + repay last acquire)
    for (int i = 0; i < 3; i++) { // only three steps, we're somewhere in the warmup period
      limiter.acquire(); // #3
    }

    limiter.setRate(4.0); // double the rate!

   * of the function, thus time. Thus, the RateLimiter becomes /faster/ after a period of
   * underutilization. If, on the other hand, we pick a function that goes /above/ that horizontal
   * line, then it means that the area (time) is increased, thus storedPermits are more costly than
   * fresh permits, thus the RateLimiter becomes /slower/ after a period of underutilization.
   *

     * @param initialDelay the time to delay first execution
     * @param period the period between successive executions of the task
     * @param unit the time unit of the initialDelay and period parameters
     */
    @SuppressWarnings("GoodTime") // should accept a java.time.Duration
    public static Scheduler newFixedRateSchedule(
        final long initialDelay, final long period, final TimeUnit unit) {
      checkNotNull(unit);

              @Override
              public ScheduledFuture<?> scheduleAtFixedRate(
                  Runnable command, long initialDelay, long period, TimeUnit unit) {
                assertSingleCallWithCorrectParameters(command, initialDelay, period, unit);
                return new ThrowingScheduledFuture<>();
              }
            },
            testRunnable);
    assertTrue(called);
  }

    @Override
    public ListenableScheduledFuture<?> scheduleAtFixedRate(
        Runnable command, long initialDelay, long period, TimeUnit unit) {
      NeverSuccessfulListenableFutureTask task = new NeverSuccessfulListenableFutureTask(command);
      ScheduledFuture<?> scheduled = delegate.scheduleAtFixedRate(task, initialDelay, period, unit);
      return new ListenableScheduledTask<@Nullable Void>(task, scheduled);
    }

    @Override

              @Override
              public ScheduledFuture<?> scheduleAtFixedRate(
                  Runnable command, long initialDelay, long period, TimeUnit unit) {
                assertSingleCallWithCorrectParameters(command, initialDelay, period, unit);
                return new ThrowingScheduledFuture<>();
              }
            },
            testRunnable);
    assertTrue(called);
  }

 * specified the JVM flag {@code -XX:+DisableExplicitGC}. But in practice, it works very well for
 * ordinary tests.
 *
 * <p>Failure of the expected event to occur within an implementation-defined "reasonable" time
 * period or an interrupt while waiting for the expected event will result in a {@link
 * RuntimeException}.
 *
 * <p>Here's an example that tests a {@code finalize} method:
 *
 * <pre>{@code

 * specified the JVM flag {@code -XX:+DisableExplicitGC}. But in practice, it works very well for
 * ordinary tests.
 *
 * <p>Failure of the expected event to occur within an implementation-defined "reasonable" time
 * period or an interrupt while waiting for the expected event will result in a {@link
 * RuntimeException}.
 *
 * <p>Here's an example that tests a {@code finalize} method:
 *
 * <pre>{@code