1846 server mqttserverstopasync doesnt indicate correct reason (#1872)

Source/MQTTnet.AspnetCore/MqttHostedServer.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
@@ -14,20 +15,27 @@ namespace MQTTnet.AspNetCore
 {
     public sealed class MqttHostedServer : MqttServer, IHostedService
     {
-        public MqttHostedServer(MqttServerOptions options, IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger) 
-            : base(options, adapters, logger)
+        readonly MqttFactory _mqttFactory;
+
+        public MqttHostedServer(MqttFactory mqttFactory, MqttServerOptions options, IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger) : base(
+            options,
+            adapters,
+            logger)
         {
+            _mqttFactory = mqttFactory ?? throw new ArgumentNullException(nameof(mqttFactory));
         }
 
-        public Task StartAsync(CancellationToken cancellationToken)
+        public async Task StartAsync(CancellationToken cancellationToken)
         {
-            _ =  StartAsync();
-            return Task.CompletedTask;
+            // The yield makes sure that the hosted service is considered up and running.
+            await Task.Yield();
+
+            _ = StartAsync();
         }
 
         public Task StopAsync(CancellationToken cancellationToken)
         {
-            return StopAsync();
+            return StopAsync(_mqttFactory.CreateMqttServerStopOptionsBuilder().Build());
         }
     }
 }