@Override
  public boolean equals(Object other) {
    if (!(other instanceof ExtendedCell)) {
      return false;
    }
    return PrivateCellUtil.equals(this, (ExtendedCell) other);
  }
Needed doing 'contains' on List. Only compares the key portion, not the value.
hbase-common/src/main/java/org/apache/hadoop/hbase/ByteBufferKeyValue.java