gt;= 10000) return &quot;0$n&quot;;
    if (n &gt;= 1000) return &quot;00$n&quot;;
    if (n &gt;= 100) return &quot;000$n&quot;;
    if (n &gt;= 10) return &quot;0000$n&quot;;
    return &quot;00000$n&quot;;
  }

  String twoDigits(int n) {
    if (n &gt;= 10) return &quot;$n&quot;;
    return &quot;0$n&quot;;
  }

  if (inMicroseconds &lt; 0) {
    return &quot;-${-this}&quot;;
  }
  String twoDigitMinutes = twoDigits(inMinutes.remainder(minutesPerHour));
  String twoDigitSeconds = twoDigits(inSeconds.rem