rebuild_test.dart

import 'package:flutter/material.dart';

class MyWidget extends StatefulWidget {
  const MyWidget({Key? key}) : super(key: key);

  @override
  State<MyWidget> createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        setState(() {
          print('triggering rebuild!');
        });
      },
      child: Column(children: [
        const MyChildWidget(
          myString: 'the const widget',
          color: Colors.red,
        ),
        MyChildWidget(
          myString: 'the regular widget',
          color: Colors.blue,
        ),
      ]),
    );
  }
}

class MyChildWidget extends StatelessWidget {
  const MyChildWidget({
    Key? key,
    required this.myString,
    required this.color,
  }) : super(key: key);

  final String myString;
  final Color color;

  @override
  Widget build(BuildContext context) {
    print('$myString was built');
    return Flexible(flex: 1, child: Container(color: color));
  }
}

void main() async {
  return runApp(const MaterialApp(home: MyWidget()));
}