anchor.diff:  
   import 'dart:async';
   import 'dart:math' as math;
  -import 'dart:math';
   
   import 'package:flutter/cupertino.dart';
   import 'package:flutter/foundation.dart';
  
positive.code:   void performResize() {
      size = Size(
        constraints.hasBoundedWidth ? constraints.maxWidth : _minPreferredTrackWidth + _maxSliderPartWidth,
        constraints.hasBoundedHeight ? constraints.maxHeight : max(_minPreferredTrackHeight, _maxSliderPartHeight),
      );
    }
  
  
negative.code:   double computeMaxIntrinsicWidth(double height) => _minPreferredTrackWidth + _maxSliderPartWidth;
  
    @override
    double computeMinIntrinsicHeight(double width) => math.max(_minPreferredTrackHeight, _maxSliderPartHeight);
  
    @override
    double computeMaxIntrinsicHeight(double width) => math.max(_minPreferredTrackHeight, _maxSliderPartHeight);
  
    @override
    bool get sizedByParent => true;
  