What is the build method in Flutter, and how frequently does Flutter actually call it to properly determine exactly what should genuinely be displayed on screen at any given specific moment?

The build method is a genuinely required method that essentially every single widget must properly implement, responsible for actually describing and returning exactly what that specific particular widget should genuinely look like at that exact current specific moment, expressed as a tree of other further nested child widgets, and Flutter automatically calls this same build method again whenever that specific widget's own inputs genuinely change, whenever setState is properly called on an associated State object, or whenever an ancestor widget higher up simply happens to rebuild for its own entirely separate unrelated reason, meaning a given specific build method can genuinely be called quite frequently, so keeping it genuinely fast and free of any expensive computation is considered an important, genuinely widely recognized best practice.

@override
Widget build(BuildContext context) {
  return Container(color: Colors.blue, child: Text('Content'));
}