public void beforeShipped() {
    if (this.prevCell != null) {
      // can't use KeyValueUtil#toNewKeyCell, because we need both key and value
      // from the prevCell in FastDiffDeltaEncoder
      this.prevCell = KeyValueUtil.copyToNewKeyValue(this.prevCell);
    }
  }
The previous Cell the encoder encoded.
hbase-common/src/main/java/org/apache/hadoop/hbase/io/encoding/EncodingState.java