How to get IHubContext in ConfigureServices?

Question

ASP.NET

How to get IHubContext in ConfigureServices, ASP.NET Core 2.1?
This implementation returns only null, and, accordingly, sending messages through the context does not work:

var provider = services.BuildServiceProvider();
            using (var scope = provider.CreateScope())
            {
                IHubContext<CrashHub> crashHub = (IHubContext<CrashHub>)scope.ServiceProvider.GetService(typeof(IHubContext<CrashHub>));
                GamesContext сrashService = new GamesContext(connection);
                services.AddSingleton<IHostedService, CrashService>(s => new CrashService(crashHub, сrashService));
            }