如何创建自定义AnimatedIcon - Flutter

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';

class CustomAnimatedIconData extends AnimatedIconData {
  const CustomAnimatedIconData(
    int _value, {
    this.color,
    this.size,
    this.semanticLabel,
    this.textDirection,
  }) : super(_value);
  
  final Color color;
  final double size;
  final String semanticLabel;
  final TextDirection textDirection;

  @override
  Widget build(BuildContext context) {
    return const SizedBox.shrink();
  }
}

class CustomAnimatedIcon extends AnimatedIcon {
  const CustomAnimatedIcon({
    Key key,
    @required Animation<double> animation,
    this.color,
    this.size,
    this.semanticLabel,
    this.textDirection,
  }) : super(key: key, listenable: animation);

  final Color color;
  final double size;
  final String semanticLabel;
  final TextDirection textDirection;

  @override
  Widget build(BuildContext context) {
    final Animation<double> animation = listenable;
    return CustomAnimatedIconData(
      animation.value.toInt(),
      color: color,
      size: size,
      semanticLabel: semanticLabel,
      textDirection: textDirection,
    );
  }
}

CustomAnimatedIcon(
  animation: animationController,
  color: Colors.blue,
  size: 24.0,
  semanticLabel: 'Custom Animated Icon',
  textDirection: TextDirection.ltr,
)