return MoreObjects.firstNonNull(subscribers.get(eventType), ImmutableSet.<Subscriber>of());
  }

  /**
   * Gets an iterator representing an immutable snapshot of all subscribers to the given event at
   * the time this method is called.
   */
  Iterator<Subscriber> getSubscribers(Object event) {
    ImmutableSet<Class<?>> eventTypes = flattenHierarchy(event.getClass());

    assertThat(undirectedGraph.edges()).isEmpty();
    assertThat(undirectedGraph.addEdge(N1, N2, E12)).isTrue();
    assertThat(undirectedGraph.edgesConnecting(N1, N2)).isEqualTo(ImmutableSet.of(E12));
    assertThat(undirectedGraph.edgesConnecting(N2, N1)).isEqualTo(ImmutableSet.of(E12));

    // By default, parallel edges are not allowed.
    IllegalArgumentException e =

  static final ImmutableTable<Object, Object, Object> EMPTY =
      new SparseImmutableTable<>(
          ImmutableList.<Cell<Object, Object, Object>>of(), ImmutableSet.of(), ImmutableSet.of());

  private final ImmutableMap<R, ImmutableMap<C, V>> rowMap;
  private final ImmutableMap<C, ImmutableMap<R, V>> columnMap;

  private final byte[] bytes;
  private final ImmutableSet<TestOption> options;

  private boolean inputStreamOpened;
  private boolean inputStreamClosed;

  TestByteSource(byte[] bytes, TestOption... options) {
    this.bytes = checkNotNull(bytes);
    this.options = ImmutableSet.copyOf(options);
  }

  @Override
  public boolean wasStreamOpened() {

    for (int i = 0; i < reps; i++) {
      dummy += algorithm.multipleQuantiles(ImmutableSet.of(90, 99), 100, dataset(i)).get(90);
    }
    return dummy;
  }

  @Benchmark
  double threePercentiles(int reps) {
    double dummy = 0.0;
    for (int i = 0; i < reps; i++) {
      dummy += algorithm.multipleQuantiles(ImmutableSet.of(90, 95, 99), 100, dataset(i)).get(90);
    }
    return dummy;
  }

  @Benchmark

    ExceptionType(Class<? extends Exception> exceptionType) {
      this.exceptionType = exceptionType;
    }
  }

  private static final ImmutableSet<Class<? extends Exception>> OTHER_EXCEPTION_TYPES =
      ImmutableSet.of(
          BackingStoreException.class,
          BrokenBarrierException.class,
          CloneNotSupportedException.class,
          DataFormatException.class,

  private static final ByteSink BROKEN_WRITE_SINK = new TestByteSink(WRITE_THROWS);

  private static final ImmutableSet<ByteSource> BROKEN_SOURCES =
      ImmutableSet.of(BROKEN_CLOSE_SOURCE, BROKEN_OPEN_SOURCE, BROKEN_READ_SOURCE);
  private static final ImmutableSet<ByteSink> BROKEN_SINKS =
      ImmutableSet.of(BROKEN_CLOSE_SINK, BROKEN_OPEN_SINK, BROKEN_WRITE_SINK);

  public void testCopyExceptions() {

  private static final ImmutableSet<Integer> TEST_INTS;
  private static final ImmutableSet<Long> TEST_LONGS;

  private static int force32(int value) {
    // GWT doesn't consistently overflow values to make them 32-bit, so we need to force it.
    return value & 0xffffffff;
  }

  static {
    ImmutableSet.Builder<Integer> testIntsBuilder = ImmutableSet.builder();

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * GWT implementation of {@link ImmutableSet} that forwards to another {@code Set} implementation.
 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
@SuppressWarnings("serial") // Serialization only done in GWT.
public abstract class ForwardingImmutableSet<E> extends ImmutableSet<E> {
  private final transient Set<E> delegate;

  ForwardingImmutableSet(Set<E> delegate) {

        .withKeyStrengths(ImmutableSet.of(Strength.STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.copyOf(Strength.values()))
        .withConcurrencyLevels(ImmutableSet.of(1, 4, 16, 64))
        .withMaximumSizes(ImmutableSet.of(400, 1000))
        .withInitialCapacities(ImmutableSet.of(0, 1, 10, 100, 1000))
        .withExpireAfterWrites(
            ImmutableSet.of(