public static async Task <TestHandler> Create(string scheme)
            {
                var handler = new TestHandler();
                var context = new DefaultHttpContext();

                context.Features.Set <IHttpResponseFeature>(new TestResponse());
                await handler.InitializeAsync(new TestOptions(), context, new LoggerFactory().CreateLogger("TestHandler"), Framework.WebEncoders.UrlEncoder.Default);

                handler.Options.AuthenticationScheme = scheme;
                return(handler);
            }