docs: public static double estimateSelectivity(
        final Iterator<ImmutableBitmap> bitmaps,
        final long totalNumRows
    )
    {
      long numMatchedRows = 0;
      while (bitmaps.hasNext()) {
        final ImmutableBitmap bitmap = bitmaps.next();
        numMatchedRows += bitmap.size();
      }
  
      return Math.min(1., (double) numMatchedRows / totalNumRows);
    }