public static ExtendedCell createCell(ExtendedCell cell, byte[] tags) {
    if (cell instanceof ByteBufferExtendedCell) {
      return new TagRewriteByteBufferExtendedCell((ByteBufferExtendedCell) cell, tags);
    }
    return new TagRewriteCell(cell, tags);
  }
Returns A new cell which is having the extra tags also added to it.
hbase-common/src/main/java/org/apache/hadoop/hbase/PrivateCellUtil.java