@SuppressWarnings("unchecked") // safe since map is not writable
      ImmutableBiMap<K, V> bimap = (ImmutableBiMap<K, V>) map;
      // TODO(lowasser): if we need to make a copy of a BiMap because the
      // forward map is a view, don't make a copy of the non-view delegate map
      if (!bimap.isPartialView()) {
        return bimap;
      }
    }
    return copyOf(map.entrySet());
  }

  /**