improved server usage in aspnet so no exceptions are thrown on startup

MQTTnet.Core/Server/IMqttServer.cs

@@ -8,6 +8,7 @@ namespace MQTTnet.Core.Server
     {
         event EventHandler<MqttClientConnectedEventArgs> ClientConnected;
         event EventHandler<MqttClientDisconnectedEventArgs> ClientDisconnected;
+        event EventHandler<MqttServerStartedEventArgs> Started;
 
         IList<ConnectedMqttClient> GetConnectedClients();
         void Publish(IEnumerable<MqttApplicationMessage> applicationMessages);

MQTTnet.Core/Server/MqttServer.cs

@@ -49,6 +49,7 @@ namespace MQTTnet.Core.Server
             return _clientSessionsManager.GetConnectedClients();
         }
 
+        public event EventHandler<MqttServerStartedEventArgs> Started;
         public event EventHandler<MqttClientConnectedEventArgs> ClientConnected;
         public event EventHandler<MqttClientDisconnectedEventArgs> ClientDisconnected;
         public event EventHandler<MqttApplicationMessageReceivedEventArgs> ApplicationMessageReceived;
@@ -96,6 +97,8 @@ namespace MQTTnet.Core.Server
             }
 
             _logger.LogInformation("Started.");
+
+            Started?.Invoke(this, new MqttServerStartedEventArgs());
         }
 
         public async Task StopAsync()

MQTTnet.Core/Server/MqttServerStartedEventArgs.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace MQTTnet.Core.Server
+{
+    public class MqttServerStartedEventArgs : EventArgs
+    {
+    }
+}

Tests/MQTTnet.TestApp.AspNetCore2/Startup.cs

@@ -5,7 +5,6 @@ using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.FileProviders;
-using Microsoft.Extensions.Logging;
 using MQTTnet.AspNetCore;
 using MQTTnet.Core;
 
@@ -21,21 +20,34 @@ namespace MQTTnet.TestApp.AspNetCore2
         }
 
         // In class _Startup_ of the ASP.NET Core 2.0 project.
-        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
+        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
         {
             app.UseMqttEndpoint();
-            app.UseMqttServer(async server =>
+            app.UseMqttServer(server =>
             {
-                var msg = new MqttApplicationMessageBuilder()
-                    .WithPayload("Mqtt is awesome")
-                    .WithTopic("message");
-
-                while (true)
+                server.Started += async (sender, args) =>
                 {
-                    server.PublishAsync(msg.Build()).Wait();
-                    await Task.Delay(TimeSpan.FromSeconds(2));
-                    msg.WithPayload("Mqtt is still awesome at " + DateTime.Now);
-                }
+                    var msg = new MqttApplicationMessageBuilder()
+                        .WithPayload("Mqtt is awesome")
+                        .WithTopic("message");
+
+                    while (true)
+                    {
+                        try
+                        {
+                            await server.PublishAsync(msg.Build());
+                            msg.WithPayload("Mqtt is still awesome at " + DateTime.Now);
+                        }
+                        catch (Exception e)
+                        {
+                            Console.WriteLine(e);
+                        }
+                        finally
+                        {
+                            await Task.Delay(TimeSpan.FromSeconds(2));
+                        }
+                    }
+                };
             });
 
             app.Use((context, next) =>