docs: @Override
    public void addLong(long x) {
      int high = high(x);
      int low = low(x);
  
      // Copy the reference to prevent race-condition
      Map.Entry<Integer, BitmapDataProvider> local = latestAddedHigh;
  
      BitmapDataProvider bitmap;
      if (local != null && local.getKey().intValue() == high) {
        bitmap = local.getValue();
      } else {
        bitmap = highToBitmap.get(high);
        if (bitmap == null) {
          bitmap = newRoaringBitmap();
          pushBitmapForHigh(high, bitmap);
        }
        latestAddedHigh = new AbstractMap.SimpleImmutableEntry<>(high, bitmap);
      }
      bitmap.add(low);
  
      invalidateAboveHigh(high);
    }