@GwtIncompatible // SerializableTester
  static <E> Set<E> reserializeAndAssertLenient(Set<E> original) {
    Set<E> copy = reserialize(original);
    assertEquals(original, copy);
    assertTrue(copy instanceof ImmutableSet);
    return copy;
  }

  @CanIgnoreReturnValue
  @GwtIncompatible // SerializableTester
  static <E> Multiset<E> reserializeAndAssertLenient(Multiset<E> original) {
    Multiset<E> copy = reserialize(original);