@J2ktIncompatible
  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();
    stream.writeInt(keySet().size());
    for (K key : keySet()) {
      stream.writeObject(key);
    }
    stream.writeInt(size());
    for (Entry<K, V> entry : entries()) {
      stream.writeObject(entry.getKey());
      stream.writeObject(entry.getValue());
    }
  }

    @J2ktIncompatible
    private void writeObject(ObjectOutputStream stream) throws IOException {
      stream.defaultWriteObject();
      stream.writeObject(inverse());
    }

    @GwtIncompatible // java.io.ObjectInputStream
    @J2ktIncompatible
    @SuppressWarnings("unchecked") // reading data stored by writeObject

      Iterators.addAll(list, iterator());
      return list;
    }
  }

  /** @serialData the ConcurrentMap of elements and their counts. */
  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();
    stream.writeObject(countMap);
  }

  @J2ktIncompatible // serialization
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {

  @J2ktIncompatible
  @GwtIncompatible // serialization
  private static Object reserialize(Object object) throws Exception {
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    new ObjectOutputStream(bytes).writeObject(object);
    return new ObjectInputStream(new ByteArrayInputStream(bytes.toByteArray())).readObject();
  }

    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    ObjectOutputStream oos = new ObjectOutputStream(bytes);
    oos.writeObject(map);
    oos.flush();

    int mapSize = bytes.size();
    oos.writeObject(keySet);
    oos.writeObject(values);
    oos.close();

    int finalSize = bytes.size();

    assertThat(finalSize - mapSize).isLessThan(100);
  }

        try {
            final ByteArrayOutputStream baos = new ByteArrayOutputStream(BYTE_ARRAY_SIZE);
            final ObjectOutputStream oos = new ObjectOutputStream(baos);
            try {
                oos.writeObject(obj);
            } finally {
                oos.close();
            }
            return baos.toByteArray();
        } catch (final IOException ex) {
            throw new IORuntimeException(ex);
        }

            ASN1OutputStream der = ASN1OutputStream.create(collector, ASN1Encoding.DER);
            DERTaggedObject derApplicationSpecific = new DERTaggedObject(false, BERTags.APPLICATION, 0, new DERSequence(ev));
            der.writeObject(derApplicationSpecific);
            return collector.toByteArray();
        }
        catch ( IOException ex ) {
            throw new IllegalStateException(ex.getMessage());
        }
    }

  @J2ktIncompatible
  @GwtIncompatible // serialization
  private static Object reserialize(Object object) throws Exception {
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    new ObjectOutputStream(bytes).writeObject(object);
    return new ObjectInputStream(new ByteArrayInputStream(bytes.toByteArray())).readObject();
  }

  }

  /** Returns the {@link #sum} as a {@code double} after a widening primitive conversion. */
  @Override
  public double doubleValue() {
    return (double) sum();
  }

  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();
    s.writeLong(sum());
  }

  private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {

   *     key, number of values for that key, and the key's values
   */
  @GwtIncompatible // java.io.ObjectOutputStream
  @J2ktIncompatible
  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();
    Serialization.writeMultimap(this, stream);
  }

  @GwtIncompatible // java.io.ObjectInputStream
  @J2ktIncompatible