code: @Override
    public int compareTo(Timestamp otherTimestamp) {
      int cmp = TimeUtils.compareLongs(getSeconds(), otherTimestamp.getSeconds());
      if (cmp != 0) {
        return cmp;
      }
      return TimeUtils.compareLongs(getNanos(), otherTimestamp.getNanos());
    }
docs: Compares this {@code Timestamp} to the specified {@code Timestamp}.
  
  @param otherTimestamp the other {@code Timestamp} to compare to, not {@code null}.
  @return the comparator value: zero if equal, negative if this timestamp happens before
  otherTimestamp, positive if after.
  @throws NullPointerException if otherTimestamp is {@code null}.