this.values = map.values();
    }

    @SuppressWarnings("unchecked")
    final Object readResolve() {
      if (!(this.keys instanceof ImmutableSet)) {
        return legacyReadResolve();
      }

      ImmutableSet<K> keySet = (ImmutableSet<K>) this.keys;
      ImmutableCollection<V> values = (ImmutableCollection<V>) this.values;