@Override
    public ExtendedCell deepClone() {
      ExtendedCell clonedBaseCell = this.cell.deepClone();
      if (clonedBaseCell instanceof ByteBufferExtendedCell) {
        return new ValueAndTagRewriteByteBufferExtendedCell((ByteBufferExtendedCell) clonedBaseCell,
          this.value, this.tags);
      }
      return new ValueAndTagRewriteCell(clonedBaseCell, this.value, this.tags);
    }
Made into a static method so as to reuse the logic within
ValueAndTagRewriteByteBufferExtendedCell
hbase-common/src/main/java/org/apache/hadoop/hbase/PrivateCellUtil.java