static <A, B> L<B> valuesArray(Map<A, B> map) {
  if (map == null) null;
  synchronized(collectionMutex(map)) {
    int n = map.size();
    B[] array = new[n];
    var it = valueIterator(map);
    for i to n:
      array[i] = it.next();
    ret array;
  }
}