anchor.diff:    ///
     /// Defaults to 1.0. Must be between 0.0 and 1.0 inclusive, and cannot be null.
     final double progress;
  -
  -  /// The iOS version style of activity indicator.
  -  ///
  -  /// Defaults to [CupertinoActivityIndicatorIOSVersionStyle.iOS14].
  -  // TODO(ctrysbita): Deprecate after official release, https://github.com/flutter/flutter/issues/62521
  -  final CupertinoActivityIndicatorIOSVersionStyle iOSVersionStyle;
   
     @override
     _CupertinoActivityIndicatorState createState() =>
  
positive.code:     @required this.activeColor,
      @required this.radius,
      @required this.progress,
      CupertinoActivityIndicatorIOSVersionStyle iOSVersionStyle =
          CupertinoActivityIndicatorIOSVersionStyle.iOS13,
    })  : alphaValues = _kAlphaValuesMap[iOSVersionStyle],
          tickFundamentalRRect = RRect.fromLTRBXY(
            -radius / _kDefaultIndicatorRadius,
            -radius /
                (iOSVersionStyle ==
                        CupertinoActivityIndicatorIOSVersionStyle.iOS14
                    ? 3.0
                    : 2.0),
            radius / _kDefaultIndicatorRadius,
            -radius,
            radius / _kDefaultIndicatorRadius,
  
negative.code:     Key key,
      this.radius = _kDefaultIndicatorRadius,
      this.progress = 1.0,
    })  : assert(radius != null),
          assert(radius > 0.0),
          assert(progress != null),
  