* #writeMultiset} for the data format.
   */
  static <E extends @Nullable Object> void populateMultiset(
      Multiset<E> multiset, ObjectInputStream stream) throws IOException, ClassNotFoundException {
    int distinctElements = stream.readInt();
    populateMultiset(multiset, stream, distinctElements);
  }

  /**

   * #writeMultiset} for the data format.
   */
  static <E extends @Nullable Object> void populateMultiset(
      Multiset<E> multiset, ObjectInputStream stream) throws IOException, ClassNotFoundException {
    int distinctElements = stream.readInt();
    populateMultiset(multiset, stream, distinctElements);
  }

  /**

    stream.defaultReadObject();
    int distinctElements = Serialization.readCount(stream);
    setBackingMap(new HashMap<>());
    Serialization.populateMultiset(this, stream, distinctElements);
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

    Class<E> localType = (Class<E>) requireNonNull(stream.readObject());
    type = localType;
    enumConstants = type.getEnumConstants();
    counts = new int[enumConstants.length];
    Serialization.populateMultiset(this, stream);
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

    AvlNode<E> header = new AvlNode<>();
    Serialization.getFieldSetter(TreeMultiset.class, "header").set(this, header);
    successor(header, header);
    Serialization.populateMultiset(this, stream);
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 1;