@Override
 public void read(PortableReader reader) throws IOException {
   super.read(reader);
   ttlMillis = reader.readLong("ttlMillis");
   ObjectDataInput in = reader.getRawDataInput();
   key = in.readData();
   value = in.readData();
 }
 @Override
 public void read(PortableReader reader) throws IOException {
   super.read(reader);
   ObjectDataInput in = reader.getRawDataInput();
   key = in.readObject();
 }