message: Add the waiting time and cross-replica-sum time to StepInfoResult.
diff: @@ -79,6 +79,10 @@ message StepInfoResult {
  optional uint64 infeed_duration_ps = 3;
  // The start time of this step in picoseconds.
  optional uint64 begin_ps = 4;
  + // The waiting time within this step in picoseconds.
  + optional uint64 wait_duration_ps = 5;
  + // The time spent on cross-replica-sum in picoseconds.
  + optional uint64 crs_duration_ps = 6;
  }
  // Result proto for a sequence of steps.
  