GaugeRange constructor
      
      GaugeRange({})
     
    
Create a range with the default or required properties.
The arguments startValue, endValue, must not be null.
Implementation
GaugeRange({
  Key? key,
  required this.startValue,
  required this.endValue,
  double? startWidth,
  double? endWidth,
  this.sizeUnit = GaugeSizeUnit.logicalPixel,
  this.color,
  this.gradient,
  this.rangeOffset = 0,
  this.label,
  GaugeTextStyle? labelStyle,
}) : startWidth =
         startWidth = startWidth ?? (label != null ? startWidth : 10),
     endWidth = endWidth = endWidth ?? (label != null ? endWidth : 10),
     labelStyle = labelStyle ?? const GaugeTextStyle(),
     assert(
       (gradient != null && gradient is SweepGradient) || gradient == null,
       'The gradient must be null or else the gradient must be equal'
       ' to sweep gradient.',
     ),
     super(key: key);