BoxScrollView constructor
Creates a ScrollView uses a single child layout model.
If the primary argument is true, the controller must be null.
Implementation
const BoxScrollView({
  Key key,
  Axis scrollDirection = Axis.vertical,
  bool reverse = false,
  ScrollController controller,
  bool primary,
  ScrollPhysics physics,
  bool shrinkWrap = false,
  this.padding,
  double cacheExtent,
  int semanticChildCount,
}) : super(
  key: key,
  scrollDirection: scrollDirection,
  reverse: reverse,
  controller: controller,
  primary: primary,
  physics: physics,
  shrinkWrap: shrinkWrap,
  cacheExtent: cacheExtent,
  semanticChildCount: semanticChildCount,
);