doLayout method
Implementation
doLayout(
RenderBox child, BoxConstraints constraints, ChildLayouter layoutChild) {
// calculate the child's size by performing
// a dry layout. We use LocalBoxConstraints in order to
// override isTight, which is used in Layout() to determine if a
// child size change forces a parent to resize.
layoutChild(child, LocalBoxConstraints.from(constraints));
// set child size in its model
if (child.parentData is BoxData) {
(child.parentData as BoxData).model?.layoutComplete(
child.size, Offset(child.paintBounds.left, child.paintBounds.top));
}
}