sclass RunResultWithTimestamps<A> extends OKOrError<A> {
  settable Timestamp started;
  settable Timestamp ended;
  settable CharSequence printOutput;

  selfType run(IF0<A> f, bool printStackTrace default true) {
    ret setPrintOutput(hijackPrint_tee(r {
      started(tsNow());
      copyFrom(okOrError(f, printStackTrace));
      ended(tsNow());
    }));
  }
  
  bool hasRun() { ret ended != null; }
  
  // legacy
  OKOrError result() { this; }
  
  Duration duration() { ret ended.minusAsDuration(started); }
  
  S renderDuration() {
    ret formatElapsedTimeWithAppropriateUnit(nanosToSeconds(duration().toNanos()));
  }
}