docs: public static long[] copy(long[] v, int mincap) {
      int words = ((mincap - 1) >>> LONG_LOG2_SIZE) + 1;
      if(v.length == words) {
        return Arrays.copyOf(v, v.length);
      }
      long[] ret = new long[words];
      System.arraycopy(v, 0, ret, 0, Math.min(v.length, words));
      return ret;
    }