docs: public double getRatioOfDataInIntersectionVolume(List<SpatialEntry>[] split, HyperBoundingBox[] mbrs) {
      final ModifiableHyperBoundingBox xMBR = SpatialUtil.intersection(mbrs[0], mbrs[1]);
      if(xMBR == null) {
        return 0.;
      }
      // Total number of entries, intersecting entries
      int[] numOf = { 0, 0 };
      countXingDataEntries(split[0], xMBR, numOf);
      countXingDataEntries(split[1], xMBR, numOf);
  
      return numOf[1] / (double) numOf[0];
    }