如何将CORS添加到.net core 3.2

Question

由于新的.net 3.2预览版不再具有带有configureServices函数的startup.cs，因此我无所适从，不知道如何实现.AddCors。添加服务的旧方法实质上是先添加然后使用服务。看起来这不再是解决问题的方法。添加CORS的正确代码是什么？

Program.cs

using System.Threading.Tasks;
using Microsoft.AspNetCore.Blazor.Hosting;
using Microsoft.Extensions.DependencyInjection;
using BlazorDemo.Shared;

namespace BlazorDemo
{
    public class Program
    {
        public static async Task Main(string[] args)
        {
            var builder = WebAssemblyHostBuilder.CreateDefault(args);

            builder.Services.AddSingleton<IDataLayer, DataLayer>();

            builder.Services.AddCors(options =>
            {
                options.AddPolicy("CorsPolicy",
                    builder => builder
                    .AllowAnyOrigin());
            });

            builder.RootComponents.Add<App>("app");

            await builder.Build().RunAsync();
        }
    }
}

Data.cs

namespace BlazorDemo.Shared
{
    public class Data
    {
        public Country[] data { get; set; }
    }
}

DataLayer.cs

using System;
using System.Threading.Tasks;
using System.Net.Http;
using Microsoft.AspNetCore.Components;

namespace BlazorDemo.Shared
{
    public interface IDataLayer
    {
        Task<Country[]> FetchCountries(string sortField, bool sortDesc);
        Task<Country[]> FetchCountries();
    }

    public class DataLayer : IDataLayer
    {
        public DataLayer(HttpClient httpClient)
        {
            this.httpClient = httpClient;
        }

        HttpClient httpClient;

        public async Task<Country[]> FetchCountries(string sortField, bool sortDesc)
        {
            var url = $"http://outlier.oliversturm.com:8080/countries?sort[0][selector]={sortField}&sort[0][desc]={sortDesc}&take=10";
            var data = await httpClient.GetJsonAsync<Data>(url);
            return data.data;
        }

        public async Task<Country[]> FetchCountries()
        {
            Country[] Countries;

            try
            {
                var url = $"http://outlier.oliversturm.com:8080/countries";
                var data = await httpClient.GetJsonAsync<Data>(url);
                Countries = ((Data)data).data;
            }
            catch (Exception e)
            {
                Country c = new Country() { name = "DD", areaKM2 = 2, population = 50, _id = e.Message };
                Countries = new Country[] { c };
            }

            return Countries;
        }
    }
}