sclass TimeCollector {
  long count, totalNanos;
  
  void addNanos(long nanos) {
    ++count;
    totalNanos += nanos;
  }
  
  toString {
    ret count == 0 ? "Empty time collector"
      : "Average time: " + formatElapsedTimeWithAppropriateUnit(nanosToSeconds(doubleRatio(totalNanos, count))) + " (n=" + count + ")";
  }
}