docs: public static RoaringBitmap bitmapOf(final long[] words) {
      // split long[] into blocks.
      // each block becomes a single container, if any bit is set
      final RoaringBitmap ans = new RoaringBitmap();
      int containerIndex = 0;
      for (int from = 0; from < words.length; from += BLOCK_LENGTH) {
        final int to = Math.min(from + BLOCK_LENGTH, words.length);
        final int blockCardinality = cardinality(from, to, words);
        if (blockCardinality > 0) {
          ans.highLowContainer.insertNewKeyValueAt(containerIndex++, Util.highbits(from * Long.SIZE),
              BitSetUtil.containerOf(from, to, blockCardinality, words));
        }
      }
      return ans;
    }