ASP.NET Core IHostingStartup that as soon as the site has started makes a request to itself then shuts itself down

ShutdownHostingStartup.cs

using System;
using System.Linq;
using System.Net.Http;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Hosting.Server;
using Microsoft.AspNetCore.Hosting.Server.Features;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

[assembly: HostingStartup(typeof(SelfShutdown.ShutdownHostingStartup))]

namespace SelfShutdown
{   
    public class ShutdownHostingStartup : IHostingStartup
    {
        public void Configure(IWebHostBuilder builder)
        {
            builder.ConfigureServices(services =>
            {
               services.AddTransient<IStartupFilter, ShutdownStartupFilter>();
            });
        }
    }

    public class ShutdownStartupFilter : IStartupFilter
    {
        private readonly IHostApplicationLifetime _appLifetime;
        private readonly IServerAddressesFeature _serverAddresses;
        private readonly ILogger<ShutdownStartupFilter> _logger;

        public ShutdownStartupFilter(IHostApplicationLifetime appLifetime, IServer server, ILogger<ShutdownStartupFilter> logger)
        {
            _appLifetime = appLifetime;
            _serverAddresses = server.Features.Get<IServerAddressesFeature>();
            _logger = logger;
        }

        public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)
        {
            return builder =>
            {
                _appLifetime.ApplicationStarted.Register(OnApplicationStarted);
                next(builder);
            };
        }

        private void OnApplicationStarted()
        {
            // Make a request to the site root to force full initialization
            var url = _serverAddresses.Addresses.FirstOrDefault(s => s.StartsWith("https://"))
                      ?? _serverAddresses.Addresses.FirstOrDefault(s => s.StartsWith("http://"));

            _logger.LogInformation("App startup completed, initiating request to {url}", url);
            
            using var http = new HttpClient();
            http.GetStringAsync(url).Wait();

            _logger.LogInformation("Request complete, requesting app shutdown");

            _appLifetime.StopApplication();
        }
    }
}