anchor.diff:  ///
   /// Durations are context independent. For example, a duration of 2 days is
   /// always 48 hours, even when it is added to a `DateTime` just when the
  -/// time zone is about to do a daylight-savings switch. (See [DateTime.add]).
  +/// time zone is about to make a daylight-savings switch. (See [DateTime.add]).
   ///
   /// Despite the same name, a `Duration` object does not implement "Durations"
   /// as specified by ISO 8601. In particular, a duration object does not keep
  
positive.code:   bool operator >=(Duration other) => this._duration >= other._duration;
  
    /// The number of entire days spanned by this [Duration].
    int get inDays => _duration ~/ Duration.microsecondsPerDay;
  
    /// The number of entire hours spanned by this [Duration].
    ///
    /// The returned value can be greater than 23.
    /// For example a duration of four days and three hours
    /// has 99 entire hours.
    int get inHours => _duration ~/ Duration.microsecondsPerHour;
  
    /// The number of whole minutes spanned by this [Duration].
    ///
    /// The returned value can be greater than 59.
    /// For example a duration of three hours and 12 minutes
    /// has 192 minutes.
    int get inMinutes => _duration ~/ Duration.microsecondsPerMinute;
  
    /// The number of whole seconds spanned by this [Duration].
    ///
    /// The returned value can be greater than 59.
    /// For example a duration of three minutes and 12 seconds
    /// has 192 seconds.
    int get inSeconds => _duration ~/ Duration.microsecondsPerSecond;
  
    /// The number of whole milliseconds spanned by this [Duration].
    ///
    /// The returned value can be greater than 999.
    /// For example a duration of three seconds and 125 milliseconds
    /// has 3125 milliseconds.
    int get inMilliseconds => _duration ~/ Duration.microsecondsPerMillisecond;
  
    /// The number of whole microseconds spanned by this [Duration].
    ///
    /// The returned value can be greater than 999999.
    /// For example a duration of three seconds, 125 milliseconds and
    /// 369 microseconds has 3125369 microseconds.
    int get inMicroseconds => _duration;
  
    /// Whether this [Duration] has the same length as [other].
  
negative.code:   /// Returns a string with hours, minutes, seconds, and microseconds, in the
    /// following format: `H:MM:SS.mmmmmm`. For example,
    /// ```dart
    /// var d = const Duration(days: 1, hours: 1, minutes: 33, microseconds: 500);
    /// print(d.toString()); // 25:33:00.000500
    ///
    /// d = const Duration(hours: 1, minutes: 10, microseconds: 500);
    /// print(d.toString()); // 1:10:00.000500
    /// ```
    String toString() {
      var microseconds = inMicroseconds;
  