React to Hosting changes

src/Microsoft.AspNetCore.Sockets/SocketsApplicationLifetimeService.cs

@@ -1,6 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.Extensions.Hosting;
 
 namespace Microsoft.AspNetCore.Sockets
@@ -14,14 +16,16 @@ namespace Microsoft.AspNetCore.Sockets
             _connectionManager = connectionManager;
         }
 
-        public void Start()
+        public Task StartAsync(CancellationToken token)
         {
             _connectionManager.Start();
+            return Task.CompletedTask;
         }
 
-        public void Stop()
+        public Task StopAsync(CancellationToken token)
         {
             _connectionManager.CloseConnections();
+            return Task.CompletedTask;
         }
     }
 }