@Override
 protected ClientMessage encodeResponse(Object response) {
   return MapExecuteOnKeysCodec.encodeResponse((List<Map.Entry<Data, Data>>) response);
 }
 @Override
 protected MapExecuteOnKeysCodec.RequestParameters decodeClientMessage(
     ClientMessage clientMessage) {
   return MapExecuteOnKeysCodec.decodeRequest(clientMessage);
 }