case 0:
        return ImmutableSet.of();
      case 1:
        return ImmutableSet.of(Iterables.getOnlyElement(set));
      default:
        return new ImmutableEnumSet<>(set);
    }
  }

  /*
   * Notes on EnumSet and <E extends Enum<E>>:
   *
   * This class isn't an arbitrary ForwardingImmutableSet because we need to
   * know that calling {@code clone()} during deserialization will return an

      case 0:
        return ImmutableSet.of();
      case 1:
        return ImmutableSet.of(Iterables.getOnlyElement(set));
      default:
        return new ImmutableEnumSet<>(set);
    }
  }

  /*
   * Notes on EnumSet and <E extends Enum<E>>:
   *
   * This class isn't an arbitrary ForwardingImmutableSet because we need to
   * know that calling {@code clone()} during deserialization will return an