Flutter:如何在in_app_purchase中调用苹果支付底板？

dependencies:
  in_app_purchase: ^0.5.2

import 'package:in_app_purchase/in_app_purchase.dart';

void main() {
  // 初始化in_app_purchase插件
  InAppPurchaseConnection.enablePendingPurchases();
  runApp(MyApp());
}

Future<void> _buyProduct(String productId) async {
  final PurchaseParam purchaseParam = PurchaseParam(
    productDetails: _productDetails[productId],
    applicationUserName: null,
  );

  // 发起购买请求
  final PurchaseResult purchaseResult =
      await InAppPurchaseConnection.instance.buyNonConsumable(
    purchaseParam: purchaseParam,
  );

  // 处理购买结果
  if (purchaseResult.status == PurchaseStatus.error) {
    // 购买失败
    print('购买失败: ${purchaseResult.error.message}');
  } else if (purchaseResult.status == PurchaseStatus.purchased) {
    // 购买成功
    print('购买成功');
  }
}