* Future} instances to be upgraded to {@code ListenableFuture} after the fact.
   */
  public static <V extends @Nullable Object> ListenableFuture<V> listenInPoolThread(
      Future<V> future) {
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future);
  }

  /**

    SettableFuture<@Nullable Void> future = SettableFuture.create();
    Object unused =
        new Object() {
          @SuppressWarnings({"removal", "Finalize"}) // b/260137033
          @Override
          protected void finalize() {
            future.set(null);
          }
        };
    unused = null; // Hint to the JIT that unused is unreachable
    GcFinalization.awaitDone(future);
    assertTrue(future.isDone());

   * completes. Cancelling the supplied future will also cancel the returned future, but cancelling
   * the returned future will have no effect on the supplied future.
   *
   * @since 15.0
   */
  public static <V extends @Nullable Object> ListenableFuture<V> nonCancellationPropagating(
      ListenableFuture<V> future) {
    if (future.isDone()) {
      return future;
    }

  public B withFeatures(Iterable<? extends Feature<?>> features) {
    for (Feature<?> feature : features) {
      this.features.add(feature);
    }
    return self();
  }

  public Set<Feature<?>> getFeatures() {
    return unmodifiableSet(features);
  }

  // Name

  private @Nullable String name;

  /** Configures this builder produce a TestSuite with the given name. */

  @SuppressWarnings("unchecked")
  static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  private final transient SortedMap<K, V> sortedDelegate;

  // The comparator used by this map.  It's the same as that of sortedDelegate,
  // except that when sortedDelegate's comparator is null, it points to a
  // non-null instance of Ordering.natural().
  // (cpovirk: Is sortedDelegate's comparator really ever null?)

  private static native String toPrecision(double value, int precision);

  @JsMethod
  static native boolean stringIsNullOrEmpty(@Nullable String string) /*-{
    return !string;
  }-*/;

  @JsMethod
  static native String nullToEmpty(@Nullable String string) /*-{
    return string || "";
  }-*/;

  @JsMethod
  static native String emptyToNull(@Nullable String string) /*-{

  /**
   * Retrieves the result of a {@code Future} known to be done but uses the {@code get(long,
   * TimeUnit)} overload in order to test that method.
   */
  static <V extends @Nullable Object> V getDoneFromTimeoutOverload(Future<V> future)
      throws ExecutionException {
    checkState(future.isDone(), "Future was expected to be done: %s", future);
    try {
      return getUninterruptibly(future, 0, SECONDS);
    } catch (TimeoutException e) {

 * public int compareTo(Foo that) {
 *   return ComparisonChain.start()
 *       .compare(this.aString, that.aString)
 *       .compare(this.anInt, that.anInt)
 *       .compare(this.anEnum, that.anEnum, Ordering.natural().nullsLast())
 *       .result();
 * }
 * }
 *
 * <p>The value of this expression will have the same sign as the <i>first nonzero</i> comparison

@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible
public enum MultisetFeature implements Feature<Multiset> {
  /**
   * Indicates that elements from {@code Multiset.entrySet()} update to reflect changes in the
   * backing multiset.
   */
  ENTRIES_ARE_VIEWS;

  @Override
  public Set<Feature<? super Multiset>> getImpliedFeatures() {
    return emptySet();
  }

  @Retention(RetentionPolicy.RUNTIME)

  }

  /**
   * Waits until the given future {@linkplain Future#isDone is done}, invoking the garbage collector
   * as necessary to try to ensure that this will happen.
   *
   * @throws RuntimeException if timed out or interrupted while waiting
   */
  @SuppressWarnings("removal") // b/260137033
  public static void awaitDone(Future<?> future) {
    if (future.isDone()) {
      return;
    }