measureItem method
Measures the size of a single widget.
Implementation
@override
double measureItem(Widget widget, [BoxConstraints? childConstraints]) {
late double size;
childManager.disposableElement(widget, (renderBox) {
renderBox.layout(childConstraints ?? this.childConstraints,
parentUsesSize: true);
size = paintExtentOf(renderBox);
});
return size;
}