Always await instead of directly returning Task

https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/blob/master/AsyncGuidance.md#prefer-asyncawait-over-directly-returning-task

The performance impact is negligible (and it's me saying that!)

Emby.Server.Implementations/Session/SessionWebSocketListener.cs

@@ -276,11 +276,11 @@ namespace Emby.Server.Implementations.Session
         /// </summary>
         /// <param name="webSocket">The WebSocket.</param>
         /// <returns>Task.</returns>
-        private Task SendForceKeepAlive(IWebSocketConnection webSocket)
+        private async Task SendForceKeepAlive(IWebSocketConnection webSocket)
         {
-            return webSocket.SendAsync(
+            await webSocket.SendAsync(
                 new ForceKeepAliveMessage(WebSocketLostTimeout),
-                CancellationToken.None);
+                CancellationToken.None).ConfigureAwait(false);
         }
     }
 }