Refactor logger. (#1247)

Source/MQTTnet.AspnetCore/Extensions/ServiceCollectionExtensions.cs

@@ -3,6 +3,7 @@ using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using MQTTnet.Adapter;
 using MQTTnet.Diagnostics;
+using MQTTnet.Diagnostics.Logger;
 using MQTTnet.Implementations;
 using MQTTnet.Server;
 
@@ -61,7 +62,7 @@ namespace MQTTnet.AspNetCore.Extensions
 
         private static IServiceCollection AddHostedMqttServer(this IServiceCollection services)
         {
-            var logger = new MqttNetLogger();
+            var logger = new MqttNetEventLogger();
 
             services.AddSingleton<IMqttNetLogger>(logger);
             services.AddSingleton<MqttHostedServer>();

Source/MQTTnet.AspnetCore/MqttHostedServer.cs

@@ -4,14 +4,14 @@ using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Hosting;
 using MQTTnet.Adapter;
-using MQTTnet.Diagnostics;
+using MQTTnet.Diagnostics.Logger;
 using MQTTnet.Server;
 
 namespace MQTTnet.AspNetCore
 {
-    public class MqttHostedServer : MqttServer, IHostedService
+    public sealed class MqttHostedServer : MqttServer, IHostedService
     {
-        private readonly IMqttServerOptions _options;
+        readonly IMqttServerOptions _options;
 
         public MqttHostedServer(IMqttServerOptions options, IEnumerable<IMqttServerAdapter> adapters, IMqttNetLogger logger) 
             : base(adapters, logger)

Source/MQTTnet.AspnetCore/MqttWebSocketServerAdapter.cs

@@ -1,12 +1,12 @@
 using Microsoft.AspNetCore.Http;
 using MQTTnet.Adapter;
-using MQTTnet.Diagnostics;
 using MQTTnet.Formatter;
 using MQTTnet.Implementations;
 using MQTTnet.Server;
 using System;
 using System.Net.WebSockets;
 using System.Threading.Tasks;
+using MQTTnet.Diagnostics.Logger;
 
 namespace MQTTnet.AspNetCore
 {