如何将大小设置为FloatingActionButton - Flutter

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('FloatingActionButton Example'),
        ),
        body: Center(
          child: Text('Press the button'),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () {
            // 按钮点击事件
          },
          mini: true, // 设置为小尺寸
          shape: CircleBorder(), // 设置为圆形
          child: Icon(Icons.add),
        ),
      ),
    );
  }
}