docs: @SuppressWarnings("unchecked")
     private static <T> T[] finishToArray(T[] r, Iterator<?> it) {
        int i = r.length;
        while (it.hasNext()) {
           int cap = r.length;
           if (i == cap) {
              int newCap = cap + (cap >> 1) + 1;
              // overflow-conscious code
              if (newCap - MAX_ARRAY_SIZE > 0)
                 newCap = hugeCapacity(cap + 1);
              r = Arrays.copyOf(r, newCap);
           }
           r[i++] = (T)it.next();
        }
        // trim if overallocated
        return (i == r.length) ? r : Arrays.copyOf(r, i);
     }