* second" (commonly referred to as <i>QPS</i>, queries per second).
   *
   * <p>The returned {@code RateLimiter} ensures that on average no more than {@code
   * permitsPerSecond} are issued during any given second, with sustained requests being smoothly
   * spread over each second. When the incoming request rate exceeds {@code permitsPerSecond} the

  static final String FIRST = "one";
  static final Double SECOND = 2.0d;

  final EventBus bus = new EventBus();

  public void testNoReentrantEvents() {
    ReentrantEventsHater hater = new ReentrantEventsHater();
    bus.register(hater);

    bus.post(FIRST);

    assertEquals(
        "ReentrantEventHater expected 2 events",
        Lists.<Object>newArrayList(FIRST, SECOND),
        hater.eventsReceived);
  }

    public void normalNormal(String first, Integer second) {
      reactToNullParameters(first, second);
    }

    /** Two-arg method with the second param Nullable. */
    @SuppressWarnings("GoodTime") // false positive; b/122617528
    public void normalNullable(String first, @Nullable Integer second) {
      reactToNullParameters(first, second);
    }

    /** Two-arg method with the first param Nullable. */

    public int compare(@Nullable String first, @Nullable String second) {
      if (first == second) {
        return 0;
      } else if (first == null) {
        return -1;
      } else if (second == null) {
        return 1;
      } else if (first.length() != second.length()) {
        return first.length() - second.length();
      } else {
        return first.compareTo(second);
      }
    }
  }

    assertTrue(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    stopwatch.sleepMillis(100);
    assertFalse(limiter.tryAcquire(0, SECONDS));
  }

  public void testTryAcquire_someWaitAllowed() {
    RateLimiter limiter = RateLimiter.create(5.0, stopwatch);
    assertTrue(limiter.tryAcquire(0, SECONDS));

  @CanIgnoreReturnValue
  public final <A extends Appendable> A appendTo(
      A appendable,
      @CheckForNull Object first,
      @CheckForNull Object second,
      @Nullable Object... rest)
      throws IOException {
    return appendTo(appendable, iterable(first, second, rest));
  }

  /**
   * Appends the string representation of each of {@code parts}, using the previously configured

   * <a href="https://github.com/google/guava/wiki/CollectionUtilitiesExplained#comparators">{@code
   * Comparators}</a>.
   *
   * @param a first value to compare, returned if less than or equal to b.
   * @param b second value to compare.
   * @throws ClassCastException if the parameters are not <i>mutually comparable</i>.
   * @since 30.0
   */
  public static <T extends Comparable<? super T>> T min(T a, T b) {

  static final String FIRST = "one";
  static final Double SECOND = 2.0d;

  final EventBus bus = new EventBus();

  public void testNoReentrantEvents() {
    ReentrantEventsHater hater = new ReentrantEventsHater();
    bus.register(hater);

    bus.post(FIRST);

    assertEquals(
        "ReentrantEventHater expected 2 events",
        Lists.<Object>newArrayList(FIRST, SECOND),
        hater.eventsReceived);
  }

   *
   * How this works is best explained with an example:
   *
   * For a RateLimiter that produces 1 token per second, every second that goes by with the
   * RateLimiter being unused, we increase storedPermits by 1. Say we leave the RateLimiter unused
   * for 10 seconds (i.e., we expected a request at time X, but we are at time X + 10 seconds before
   * a request actually arrives; this is also related to the point made in the last paragraph), thus

  @GwtIncompatible
  public Class<K> keyType() {
    return keyTypeOrObjectUnderJ2cl;
  }

  /**
   * @serialData the key class, number of entries, first key, first value, second key, second value,
   *     and so on.
   */
  @GwtIncompatible // java.io.ObjectOutputStream
  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();