),

72
72

],

73
73

),

4. Set duration

Finally, set the duration of the animation that powers the transition
between the old and new values:

{container4 → container5}/lib/main.dart

@@ -2,12 +2,12 @@

2
2

// Use of this source code is governed by a BSD-style license

3
3

// that can be found in the LICENSE file.

// ignore_for_file: missing_required_argument

6
4

import 'dart:math';

7
5

import 'package:flutter/material.dart';

+
            const _duration = Duration(milliseconds: 400);