RateLimiter rateLimiter = new SmoothWarmingUp(stopwatch, warmupPeriod, unit, coldFactor);
    rateLimiter.setRate(permitsPerSecond);
    return rateLimiter;
  }

  /**
   * The underlying timer; used both to measure elapsed time and sleep as necessary. A separate
   * object to facilitate testing.
   */
  private final SleepingStopwatch stopwatch;

  On this the White Rabbit blew three blasts on the trumpet, and
then unrolled the parchment scroll, and read as follows:--

    `The Queen of Hearts, she made some tarts,
          All on a summer day:
      The Knave of Hearts, he stole those tarts,
          And took them quite away!'

  `Consider your verdict,' the King said to the jury.

   *
   * @param trimmer a {@link CharMatcher} that determines whether a character should be removed from
   *     the beginning/end of a subsequence
   * @return a splitter with the desired configuration
   */
  // TODO(kevinb): throw if a trimmer was already specified!
  public Splitter trimResults(CharMatcher trimmer) {
    checkNotNull(trimmer);

    Future<?> localTimer = timer;
    // Try to cancel the timer as an optimization.
    // timer may be null if this call to run was by the timer task since there is no happens-before
    // edge between the assignment to timer and an execution of the timer task.
    if (localTimer != null) {
      localTimer.cancel(false);
    }

    delegateRef = null;
    timer = null;
  }

      producer.beganProducing.await();

      // make sure we time out
      Stopwatch timer = Stopwatch.createStarted();

      int drained = drain(q, newArrayList(), 2, 10, MILLISECONDS, interruptibly);
      assertThat(drained).isAtMost(1);

      assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);

    assertThat(startupTimes).hasSize(2);
    assertThat(startupTimes.get(a)).isAtLeast(150);
    // Service b startup takes at least 353 millis, but starting the timer is delayed by at least
    // 150 milliseconds. so in a perfect world the timing would be 353-150=203ms, but since either
    // of our sleep calls can be arbitrarily delayed we should just assert that there is a time

   *
   * @param trimmer a {@link CharMatcher} that determines whether a character should be removed from
   *     the beginning/end of a subsequence
   * @return a splitter with the desired configuration
   */
  // TODO(kevinb): throw if a trimmer was already specified!
  public Splitter trimResults(CharMatcher trimmer) {
    checkNotNull(trimmer);

      producer.beganProducing.await();

      // make sure we time out
      Stopwatch timer = Stopwatch.createStarted();

      int drained = drain(q, newArrayList(), 2, 10, MILLISECONDS, interruptibly);
      assertThat(drained).isAtMost(1);

      assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);

    assertThat(startupTimes).hasSize(2);
    assertThat(startupTimes.get(a)).isAtLeast(150);
    // Service b startup takes at least 353 millis, but starting the timer is delayed by at least
    // 150 milliseconds. so in a perfect world the timing would be 353-150=203ms, but since either
    // of our sleep calls can be arbitrarily delayed we should just assert that there is a time

        setState(finalState);
        return true;
      }

      /**
       * Blocks until the task is complete or the timeout expires. Throws a {@link TimeoutException}
       * if the timer expires, otherwise behaves like {@link #get()}.
       */
      V get(long nanos)
          throws TimeoutException, CancellationException, ExecutionException, InterruptedException {