protected void cloneBitMap(TVList cloneList) {
    if (bitMap != null) {
      cloneList.bitMap = new ArrayList<>(bitMap.size());
      for (BitMap bm : bitMap) {
        cloneList.bitMap.add(bm == null ? null : bm.clone());
      }
    }
  }
Get whether value is null at the given position in TvList.

@param unsortedRowIndex value index
@return boolean
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/utils/datastructure/TVList.java