如何在isolate中加载和解析Json？

import 'dart:convert';
import 'dart:isolate';

void main() async {
  final receivePort = ReceivePort();
  await Isolate.spawn(isolateFunction, receivePort.sendPort);

  final sendPort = await receivePort.first;
  final jsonData = await sendReceive(sendPort, 'https://example.com/data.json');
  final parsedData = json.decode(jsonData);

  print(parsedData);
}

void isolateFunction(SendPort sendPort) async {
  final receivePort = ReceivePort();
  sendPort.send(receivePort.sendPort);

  await for (final message in receivePort) {
    final jsonData = await fetchData(message);
    sendPort.send(jsonData);
  }
}

Future<String> fetchData(String url) async {
  // 使用http或dio库发送HTTP请求获取Json数据
  // 省略具体实现
}

Future<dynamic> sendReceive(SendPort sendPort, dynamic message) {
  final receivePort = ReceivePort();
  sendPort.send([message, receivePort.sendPort]);
  return receivePort.first;
}