message: Added timing to DataFrame performance tests
diff: @@ -39,6 +39,8 @@ typedef StdDataFrame<time_t> MyDataFrame;
  int main(int argc, char *argv[]) {
  + std::cout << "Starting ... " << time(nullptr) << std::endl;
  +
  MyDataFrame df;
  auto index_vec =
  MyDataFrame::gen_datetime_index("01/01/1970", "08/15/2019", time_frequency::secondly, 1);
  @@ -49,7 +51,7 @@ int main(int argc, char *argv[]) {
  std::make_pair("log_normal", gen_lognormal_dist<double>(index_sz)),
  std::make_pair("exponential", gen_exponential_dist<double>(index_sz)));
  - std::cout << "All memory allocations are done. Calculating means ..." << std::endl;
  + std::cout << "All memory allocations are done. Calculating means ... " << time(nullptr)<< std::endl;
  MeanVisitor<double, time_t> n_mv;
  MeanVisitor<double, time_t> ln_mv;
  @@ -62,6 +64,7 @@ int main(int argc, char *argv[]) {
  std::cout << fut1.get().get_result() << ", "
  << fut2.get().get_result() << ", "
  << fut3.get().get_result() << std::endl;
  + std::cout << time(nullptr) << " ... Done" << std::endl;
  return (0);
  }
  