public Set<E> elementSet() {
      Set<E> es = elementSet;
      return (es == null) ? elementSet = createElementSet() : es;
    }

    @LazyInit @CheckForNull transient Set<Multiset.Entry<E>> entrySet;

    @SuppressWarnings("unchecked")
    @Override
    public Set<Multiset.Entry<E>> entrySet() {
      Set<Multiset.Entry<E>> es = entrySet;
      return (es == null)