message: Cast return value that caused warning
  The member function num_runs() returns an int, however the return value from run_total_us_.count() is an int64. Casting the value to an int allows for the compiler to know that the intended return value should be an int.
diff: @@ -186,7 +186,7 @@ class StatSummarizer {
  void Reset();
  // Returns number of runs.
  - int num_runs() const { return run_total_us_.count(); }
  + int num_runs() const { return static_cast<int>(run_total_us_.count()); }
  // Returns stats of total microseconds spent by all nodes in each run.
  const Stat<int64>& run_total_us() const { return run_total_us_; }
  