anchor.diff:      assert(child is RenderSector);
       assert(child.parentData is SectorParentData);
       assert(!constraints.isInfinite);
  -    double maxChildDeltaRadius = math.max(constraints.maxWidth, constraints.maxHeight) / 2.0 - innerRadius;
  +    double maxChildDeltaRadius = math.min(constraints.maxWidth, constraints.maxHeight) / 2.0 - innerRadius;
       SectorDimensions childDimensions = child.getIntrinsicDimensions(new SectorConstraints(maxDeltaRadius: maxChildDeltaRadius), innerRadius);
       double dimension = (innerRadius + childDimensions.deltaRadius) * 2.0;
       return new BoxDimensions.withConstraints(constraints, width: dimension, height: dimension);
  
positive.code:     double childRadius = radius + padding;
      double paddingTheta = math.atan(padding / (radius + outerDeltaRadius));
      double innerTheta = paddingTheta; // increments with each child
      double remainingTheta = constraints.maxDeltaTheta - (innerTheta + paddingTheta);
      RenderSector child = firstChild;
      while (child != null) {
        SectorConstraints innerConstraints = new SectorConstraints(
          maxDeltaRadius: innerDeltaRadius,
          maxDeltaTheta: remainingTheta
        );
        SectorDimensions childDimensions = child.getIntrinsicDimensions(innerConstraints, childRadius);
        innerTheta += childDimensions.deltaTheta;
        remainingTheta -= childDimensions.deltaTheta;
        assert(child.parentData is SectorChildListParentData);
        child = child.parentData.nextSibling;
        if (child != null) {
          innerTheta += paddingTheta;
          remainingTheta -= paddingTheta;
        }
      }
      return new SectorDimensions.withConstraints(constraints,
  
negative.code:     this.minDeltaRadius: 0.0,
      this.maxDeltaRadius: double.INFINITY,
      this.minDeltaTheta: 0.0,
      this.maxDeltaTheta: kTwoPi
    });
  
    const SectorConstraints.tight({ double deltaRadius: 0.0, double deltaTheta: 0.0 })
      : minDeltaRadius = deltaRadius,
  