Migrate to null-safety? about conditional-builder HOT 2 OPEN

import 'package:flutter/material.dart';

class ConditionalBuilder extends StatelessWidget {
  /// Condition to control what gets rendered.
  final bool condition;

  /// Run if [condition] is true.
  final WidgetBuilder builder;

  /// Run if [condition] is false and it is not null.
  final WidgetBuilder? fallback;

  const ConditionalBuilder({
    Key? key,
    required this.condition,
    required this.builder,
    this.fallback,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) => condition
      ? builder(context)
      : fallback != null
          ? fallback!(context)
          : Container();
}