how to initialize children widget in flutter code example

Example: how to rebuild widget in flutter in time intervals

import 'package:timer_builder/timer_builder.dart';

class ClockWidget extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return TimerBuilder.periodic(Duration(seconds: 1),
      builder: (context) {
        return Text("${DateTime.now()}");
      }
    );
  }
  
}