static long calcEstimatedSize(Result rs) {
    long estimatedHeapSizeOfResult = 0;
    // We don't make Iterator here
    for (Cell cell : rs.rawCells()) {
      estimatedHeapSizeOfResult += cell.heapSize();
    }
    return estimatedHeapSizeOfResult;
  }
Create a row before the specified row and very close to the specified row.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/ConnectionUtils.java