使用Flutter的CustomPaint，是否可以绘制具有纯色边缘的透明路径？

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'CustomPaint Example',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text('CustomPaint Example'),
        ),
        body: Center(
          child: CustomPaint(
            painter: MyPainter(),
            size: Size(200, 200),
          ),
        ),
      ),
    );
  }
}

class MyPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    final double strokeWidth = 4.0; // 边缘宽度
    final Color strokeColor = Colors.red; // 边缘颜色

    final Paint strokePaint = Paint()
      ..color = strokeColor
      ..style = PaintingStyle.stroke
      ..strokeWidth = strokeWidth;

    final Path edgePath = Path()
      ..moveTo(strokeWidth / 2, strokeWidth / 2)
      ..lineTo(size.width - strokeWidth / 2, strokeWidth / 2)
      ..lineTo(size.width - strokeWidth / 2, size.height - strokeWidth / 2)
      ..lineTo(strokeWidth / 2, size.height - strokeWidth / 2)
      ..close();

    final Path transparentPath = Path()
      ..moveTo(size.width / 2, strokeWidth)
      ..lineTo(size.width - strokeWidth, size.height / 2)
      ..lineTo(size.width / 2, size.height - strokeWidth)
      ..lineTo(strokeWidth, size.height / 2)
      ..close();

    canvas.drawPath(edgePath, strokePaint);
    canvas.drawPath(transparentPath, Paint());
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) => false;
}