message: Write proto in binary format instead of text format.
diff: @@ -213,9 +213,10 @@ int Main(int argc, char* argv[]) {
  evaluator->EvaluateModel();
  if (!proto_output_file_path.empty()) {
  - std::ofstream proto_out_file(proto_output_file_path, std::ios::out);
  + std::ofstream proto_out_file(proto_output_file_path,
  + std::ios::out | std::ios::binary);
  TopkAccuracyEvalMetrics metrics = results_writer.AggregatedMetrics();
  - proto_out_file << metrics.DebugString();
  + proto_out_file << metrics.SerializeAsString();
  proto_out_file.close();
  }
  