@Override
  public void addLastBloomKey(Writer writer) throws IOException {
    if (this.getLastCell() != null) {
      ExtendedCell firstOnRow = PrivateCellUtil.createFirstOnRowCol(this.getLastCell());
      // This copy happens only once when the writer is closed
      byte[] key = PrivateCellUtil.getCellKeySerializedAsKeyValueKey(firstOnRow);
      writer.appendFileInfo(LAST_BLOOM_KEY, key);
    }
  }
Handles ROWCOL bloom related context. It can work with both BytebufferdCells and byte[] backed
cells
hbase-server/src/main/java/org/apache/hadoop/hbase/util/RowColBloomContext.java