/**
     * @serialData the factory and the backing map
     */
    @GwtIncompatible
    @J2ktIncompatible
        private void writeObject(ObjectOutputStream stream) throws IOException {
      stream.defaultWriteObject();
      stream.writeObject(factory);
      stream.writeObject(backingMap());
    }

    @GwtIncompatible
    @J2ktIncompatible
        @SuppressWarnings("unchecked") // reading data stored by writeObject

    /**
     * @serialData the factory and the backing map
     */
    @GwtIncompatible
    @J2ktIncompatible
        private void writeObject(ObjectOutputStream stream) throws IOException {
      stream.defaultWriteObject();
      stream.writeObject(factory);
      stream.writeObject(backingMap());
    }

    @GwtIncompatible
    @J2ktIncompatible
        @SuppressWarnings("unchecked") // reading data stored by writeObject

      super(
          keyStrength, valueStrength, keyEquivalence, valueEquivalence, concurrencyLevel, delegate);
    }

    private void writeObject(ObjectOutputStream out) throws IOException {
      out.defaultWriteObject();
      writeMapTo(out);
    }

    @J2ktIncompatible // java.io.ObjectInputStream
    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {