Cleanup CancellationToken code

test/ANCMStressTestApp/Program.cs

@@ -17,9 +17,6 @@ namespace ANCMStressTestApp
 {
     public class Program
     {
-        public static IApplicationLifetime AppLifetime;
-        public static CancellationTokenSource Cts = new CancellationTokenSource();
-
         public static void Main(string[] args)
         {
             var host = new WebHostBuilder()
@@ -32,14 +29,6 @@ namespace ANCMStressTestApp
                 .UseStartup<Startup>()
                 .Build();
 
-            AppLifetime = (IApplicationLifetime)host.Services.GetService(typeof(IApplicationLifetime));
-            AppLifetime.ApplicationStopping.Register(
-                () => {
-                    Cts.Cancel();
-                    Cts.Dispose();
-                }
-            );
-
             host.Run();
         }
     }

test/ANCMStressTestApp/Startup.cs

@@ -171,7 +171,9 @@ namespace ANCMStressTestApp
                 // Get the WebSocket object
                 var ws = WebSocketProtocol.CreateFromStream(opaqueTransport, isServer: true, subProtocol: null, keepAliveInterval: TimeSpan.FromMinutes(2));
 
-                await Echo(ws, Program.Cts.Token);
+                var appLifetime = app.ApplicationServices.GetRequiredService<IApplicationLifetime>();
+
+                await Echo(ws, appLifetime.ApplicationStopping);
             });
         }