code: func ParseTimestamp(usec int64) time.Time {
  	if usec == 0 {
  		return time.Time{}
  	}
  	// TODO(nodir): will start to overflow in year ~2250+, fix it then.
  	return time.Unix(0, usec*1000).UTC()
  }
docs: // ParseTimestamp parses a buildbucket timestamp.