public static IServiceBuilder <TService> UseStartup <TService, TStartup>(this IServiceBuilder <TService> serviceBuilder)
            where TStartup : class, IStartup
        {
            var startup = serviceBuilder.GetStartupInstance <TStartup>();

            serviceBuilder.UseStartup(startup);

            return(serviceBuilder);
        }
        public static IServiceBuilder UseStartup <TStartup>(this IServiceBuilder serviceBuilder)
            where TStartup : class, IStartup
        {
            // Get the startup instance.
            var startup = serviceBuilder.GetStartupInstance <TStartup>();

            serviceBuilder.UseStartup(startup);

            return(serviceBuilder);
        }