/** Constructor for use by subclasses. */
    protected SleepingStopwatch() {}

    /*
     * We always hold the mutex when calling this. TODO(cpovirk): Is that important? Perhaps we need
     * to guarantee that each call to reserveEarliestAvailable, etc. sees a value >= the previous?
     * Also, is it OK that we don't hold the mutex when sleeping?
     */
    protected abstract long readMicros();

    stopwatch.sleepMillis(4000); // #3: becomes cold again
    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // // #4
    }
    stopwatch.sleepMillis(500); // #5: to repay for the last acquire
    stopwatch.sleepMillis(2000); // #6: didn't get cold! It would take another 2 seconds to go cold
    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // #7
    }
    assertEvents(

    stopwatch.sleepMillis(4000); // #3: becomes cold again
    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // // #4
    }
    stopwatch.sleepMillis(500); // #5: to repay for the last acquire
    stopwatch.sleepMillis(2000); // #6: didn't get cold! It would take another 2 seconds to go cold
    for (int i = 0; i < 8; i++) {
      limiter.acquire(); // #7
    }
    assertEvents(

   * implementation, because {@code map.get()} returns a view collection that changes in the course
   * of a call to {@code remove()}. Thus, the expectation doesn't hold that {@code map.remove(x)}
   * returns the same value which {@code map.get(x)} did immediately beforehand.
   */
  @Override
  public void testRemove() {
    final Map<String, Collection<Integer>> map;

    }

    @Override
    public boolean isEmpty() {
      assertTrue(Thread.holdsLock(mutex));
      return super.isEmpty();
    }

    /* Don't test iterator(); it may or may not hold the mutex. */

    @Override
    public boolean remove(@Nullable Object o) {
      assertTrue(Thread.holdsLock(mutex));
      return super.remove(o);
    }

    @Override

  public static <K extends @Nullable Object, V extends @Nullable Object>
      HashMultimap<K, V> create() {
    return new HashMultimap<>();
  }

  /**
   * Constructs an empty {@code HashMultimap} with enough capacity to hold the specified numbers of
   * keys and values without rehashing.
   *
   * <p>This method will soon be deprecated in favor of {@code
   * MultimapBuilder.hashKeys(expectedKeys).hashSetValues(expectedValuesPerKey).build()}.

   * <i>should</i> hold {@code expectedSize} elements without rebuilding internal data structures.
   *
   * @param expectedSize the number of elements you expect to add to the returned set
   * @return a new, empty {@code CompactLinkedHashMap} with enough capacity to hold {@code
   *     expectedSize} elements without resizing

 * formed by a combination of group id, artifact id, version and tag. The first three components generally refer to the
 * identity of a model. The tag allows for further classification of the associated data on the sole discretion of the
 * model builder.
 *
 */
public interface ModelCache {

    <T> T computeIfAbsent(String groupId, String artifactId, String version, String tag, Supplier<T> data);

   * <i>should</i> hold {@code expectedSize} elements without rebuilding internal data structures.
   *
   * @param expectedSize the number of elements you expect to add to the returned set
   * @return a new, empty {@code CompactLinkedHashSet} with enough capacity to hold {@code
   *     expectedSize} elements without resizing

  /**
   * Creates a {@code CompactHashSet} instance, with a high enough "initial capacity" that it
   * <i>should</i> hold {@code expectedSize} elements without growth.
   *
   * @param expectedSize the number of elements you expect to add to the returned set
   * @return a new, empty {@code CompactHashSet} with enough capacity to hold {@code expectedSize}
   *     elements without resizing