@Override
 public void readFrom(StreamInput in) throws IOException {
   super.readFrom(in);
   if (in.readBoolean()) {
     storeFilesMetaData = StoreFilesMetaData.readStoreFilesMetaData(in);
   }
 }
 @Override
 public void writeTo(StreamOutput out) throws IOException {
   super.writeTo(out);
   if (storeFilesMetaData == null) {
     out.writeBoolean(false);
   } else {
     out.writeBoolean(true);
     storeFilesMetaData.writeTo(out);
   }
 }
 public static StoreFilesMetaData readStoreFilesMetaData(StreamInput in) throws IOException {
   StoreFilesMetaData md = new StoreFilesMetaData();
   md.readFrom(in);
   return md;
 }