this.delegate = delegate;
    }

    @Override
    protected Map<K, V> delegate() {
      return delegate;
    }

    @Override
    public Set<K> keySet() {
      return new ForwardingSet<K>() {
        @Override
        protected Set<K> delegate() {
          return delegate.keySet();
        }

        @Override
        public Iterator<K> iterator() {

  @Override
  public Set<K> keySet() {
    Set<K> result = keySet;
    return (result == null) ? keySet = new KeySet() : result;
  }

  @WeakOuter
  private class KeySet extends ForwardingSet<K> {
    @Override
    protected Set<K> delegate() {
      return delegate.keySet();
    }

    @Override
    public void clear() {
      AbstractBiMap.this.clear();
    }

    @Override

                      @Override
                      public Set<Entry<String>> entrySet() {
                        final Set<Entry<String>> backingSet = super.entrySet();
                        return new ForwardingSet<Entry<String>>() {
                          @Override
                          protected Set<Entry<String>> delegate() {
                            return backingSet;
                          }

                      @Override
                      public Set<Entry<String>> entrySet() {
                        final Set<Entry<String>> backingSet = super.entrySet();
                        return new ForwardingSet<Entry<String>>() {
                          @Override
                          protected Set<Entry<String>> delegate() {
                            return backingSet;
                          }

          return true;
        }
      }
    }
    return false;
  }

  // Views

  @Override
  Set<E> createElementSet() {
    Set<E> delegate = countMap.keySet();
    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return delegate;
      }

      @Override
      public boolean contains(@CheckForNull Object object) {

              .that(immutableCopy)
              .isIn(distinctCandidatesByAscendingSize);
        }
      }
    }
  }

  private static final class MutatedOnQuerySet<E> extends ForwardingSet<E> {
    final Iterator<ImmutableSet<E>> infiniteCandidates;

    MutatedOnQuerySet(Iterable<ImmutableSet<E>> infiniteCandidates) {
      this.infiniteCandidates = infiniteCandidates.iterator();
    }

    CountingSupplier<Set<Integer>> factory =
        new SetSupplier() {
          @Override
          public Set<Integer> getImpl() {
            final Set<Integer> backing = super.getImpl();
            return new ForwardingSet<Integer>() {
              @Override
              protected Set<Integer> delegate() {
                return backing;
              }

              @Override