RichText(
  text: TextSpan(
    children: [
      TextSpan(text: ‘Обычный текст. ‘, style: TextStyle(fontSize: 14, color: Colors.black)),
      TextSpan(text: Жирный текст. ‘, style: TextStyle(fontSize: 14, color: Colors.black, fontWeight: FontWeight.bold)),
      TextSpan(text: ‘Снова обычный текст.‘, style: TextStyle(fontSize: 14, color: Colors.black)),
    ],
  ),
);

Text.rich(
  TextSpan(
    children: [
      TextSpan(text: ‘Обычный текст. ‘),
      TextSpan(text: Жирный текст. ‘, style: TextStyle(fontSize: 14, color: Colors.black, fontWeight: FontWeight.bold)),
      TextSpan(text: ‘Снова обычный текст.‘),
    ],
  ),
);

@override
void initState() {
  super.initState();

  // Your code here
}

@override
void dispose() {
  // Your code here

  super.dispose();
}

@override
Future<void> dispose() async {
  // Your code here

  super.dispose();
}

extension DateTimeX on DateTime {
  bool get isToday {
    final now = DateTime.now();
    return day == now.day && month == now.month && year == now.year;
  }

  bool get isTomorrow {
    final tomorrow = DateTime.now().add(Duration(days: 1));
    return day == tomorrow.day + 1 && month == tomorrow.month && year == tomorrow.year;
  }

  bool get isYesterday {
    final yesterday = DateTime.now().subtract(Duration(days: 1));
    return day == yesterday.day - 1 && month == yesterday.month && year == yesterday.year;
  }
}

extension DateTimeX on DateTime {
  int get daysDiff => this.difference(DateTime.now).inDays;
}

AnimatedBuilder(
  animation: _controller,
  child: Container(
    width: 200.0,
    height: 200.0,
    color: Colors.green,
    child: const Center(child: Text('Whee!')),
  ),
  builder: (BuildContext context, Widget? child) {
    return Transform.rotate(
      angle: _controller.value * 2.0 * math.pi,
      child: child,
    );
  },
),

TickerMode(
  enabled: _enabled,
  child: ...
);