@J2ktIncompatible
    @Override
        Object writeReplace() {
      return new EntrySetSerializedForm<E>(ImmutableMultiset.this);
    }

    @GwtIncompatible
    @J2ktIncompatible
        private void readObject(ObjectInputStream stream) throws InvalidObjectException {
      throw new InvalidObjectException("Use EntrySetSerializedForm");
    }