How does calling setState actually genuinely work internally, and why does Flutter genuinely require that you explicitly call it rather than simply automatically detecting a state change entirely on its own?

Calling setState explicitly notifies the Flutter framework that a specific State object's own internal data has genuinely changed and that its own particular corresponding widget therefore genuinely now needs to be properly rebuilt to correctly and accurately reflect that specific change, and Flutter genuinely requires this explicit specific call rather than simply automatically detecting any change entirely on its own, since Dart itself has no genuinely reliable, efficient built in mechanism for automatically observing every single possible mutation to an arbitrary regular object's own internal fields, meaning explicitly calling setState gives Flutter a clear, precise, and genuinely efficient specific signal for exactly when it actually genuinely needs to schedule a fresh new rebuild.

void _incrementCounter() {
  setState(() {
    _counter++;
  });
}