message: Replace CHECK() with a WARNING in StepStatsCollector so that Save after Finalize won't crash.
diff: @@ -253,7 +253,9 @@ void StepStatsCollector::Save(const string& device,
  VLOG(1) << "Save dev " << device << " nt " << stats->stats();
  {
  mutex_lock l(mu_);
  - CHECK(!finalized_);
  + if (finalized_) {
  + LOG(WARNING) << "stats saved after finalize will not be collected.";
  + }
  if (!step_stats_ || collectedNodes >= kMaxCollectedNodes) {
  VLOG(1) << "step_stats_ nullptr or already collected too many nodes.";
  delete stats;
  