@SuppressWarnings("unchecked")
    @Override
    public Set<Multiset.Entry<E>> entrySet() {
      Set<Multiset.Entry<E>> es = entrySet;
      return (es == null)
          // Safe because the returned set is made unmodifiable and Entry
          // itself is readonly
          ? entrySet = (Set) Collections.unmodifiableSet(delegate.entrySet())
          : es;
    }

    @Override
    public Iterator<E> iterator() {

     *
     * @param element the element to add
     * @param occurrences the number of occurrences of the element to add. May be zero, in which
     *     case no change will be made.
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code element} is null
     * @throws IllegalArgumentException if {@code occurrences} is negative, or if this operation

     *
     * @param element the element to add
     * @param occurrences the number of occurrences of the element to add. May be zero, in which
     *     case no change will be made.
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code element} is null
     * @throws IllegalArgumentException if {@code occurrences} is negative, or if this operation

   * X-Device-IP}</a> header field name. Header used for VAST requests to provide the IP address of
   * the device on whose behalf the request is being made.
   *
   * @since 31.0
   */
  public static final String X_DEVICE_IP = "X-Device-IP";
  /**
   * The HTTP <a
   * href="https://iabtechlab.com/wp-content/uploads/2019/06/VAST_4.2_final_june26.pdf">{@code