AspNet vNext 上的 Kestrel 不提供 下的索引页面

在 AspNet vNext 上，Kestrel 是一个轻量级的跨平台的 Web 服务器，它可以用于托管 ASP.NET 应用程序。然而，Kestrel 在默认配置下不提供根目录（/）下的索引页面。即使在访问根目录时，Kestrel 也不会自动返回一个默认的索引页面，而是返回一个 404 错误页面。

csharp
public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup();
            webBuilder.ConfigureKestrel(options =>
            {
                options.Listen(IPAddress.Any, 5000, listenOptions =>
                {
                    listenOptions.UseHttps();
                    listenOptions.UseStaticFiles();
                    listenOptions.UseDefaultFiles(new DefaultFilesOptions
                    {
                        DefaultFileNames = new List { "index.html" }
                    });
                });
            });
        });

csharp
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        // 添加所需的服务
    }
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseHsts();
        }
        app.UseHttpsRedirection();
        app.UseStaticFiles();
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
            endpoints.MapFallbackToFile("index.html");
        });
    }
}
public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }
    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup();
                webBuilder.ConfigureKestrel(options =>
                {
                    options.Listen(IPAddress.Any, 5000, listenOptions =>
                    {
                        listenOptions.UseHttps();
                        listenOptions.UseStaticFiles();
                        listenOptions.UseDefaultFiles(new DefaultFilesOptions
                        {
                            DefaultFileNames = new List { "index.html" }
                        });
                    });
                });
            });
}