Refactor logging and add benchmark.

Tests/MQTTnet.Benchmarks/LoggerBenchmark.cs

@@ -0,0 +1,54 @@
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Attributes.Exporters;
+using BenchmarkDotNet.Attributes.Jobs;
+using MQTTnet.Diagnostics;
+
+namespace MQTTnet.Benchmarks
+{
+    [ClrJob]
+    [RPlotExporter]
+    [MemoryDiagnoser]
+    public class LoggerBenchmark
+    {
+        private IMqttNetLogger _logger;
+        private IMqttNetChildLogger _childLogger;
+        private bool _useHandler;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            _logger = new MqttNetLogger("1");
+            _childLogger = _logger.CreateChildLogger("child");
+
+            MqttNetGlobalLogger.LogMessagePublished += OnLogMessagePublished;
+        }
+
+        private void OnLogMessagePublished(object sender, MqttNetLogMessagePublishedEventArgs eventArgs)
+        {
+            if (_useHandler)
+            {
+                eventArgs.TraceMessage.ToString();
+            }
+        }
+
+        [Benchmark]
+        public void Log_10000_Messages_NoHandler()
+        {
+            _useHandler = false;
+            for (var i = 0; i < 10000; i++)
+            {
+                _childLogger.Verbose("test log message {0}", "parameter");
+            }
+        }
+
+        [Benchmark]
+        public void Log_10000_Messages_WithHandler()
+        {
+            _useHandler = true;
+            for (var i = 0; i < 10000; i++)
+            {
+                _childLogger.Verbose("test log message {0}", "parameter");
+            }
+        }
+    }
+}

Tests/MQTTnet.Benchmarks/MQTTnet.Benchmarks.csproj

@@ -147,6 +147,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="LoggerBenchmark.cs" />
     <Compile Include="MessageProcessingBenchmark.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

Tests/MQTTnet.Benchmarks/Program.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Threading;
 using BenchmarkDotNet.Running;
 using MQTTnet.Diagnostics;
 
@@ -12,6 +11,7 @@ namespace MQTTnet.Benchmarks
             Console.WriteLine($"MQTTnet - BenchmarkApp.{TargetFrameworkInfoProvider.TargetFramework}");
             Console.WriteLine("1 = MessageProcessingBenchmark");
             Console.WriteLine("2 = SerializerBenchmark");
+            Console.WriteLine("3 = LoggerBenchmark");
 
             var pressedKey = Console.ReadKey(true);
             switch (pressedKey.KeyChar)
@@ -22,7 +22,8 @@ namespace MQTTnet.Benchmarks
                 case '2':
                     BenchmarkRunner.Run<SerializerBenchmark>();
                     break;
-                default:
+                case '3':
+                    BenchmarkRunner.Run<LoggerBenchmark>();
                     break;
             }
 

Tests/MQTTnet.Benchmarks/SerializerBenchmark.cs

@@ -1,9 +1,7 @@
 using BenchmarkDotNet.Attributes;
-using MQTTnet.Client;
 using MQTTnet.Packets;
 using MQTTnet.Serializer;
 using MQTTnet.Internal;
-using MQTTnet.Server;
 using BenchmarkDotNet.Attributes.Jobs;
 using BenchmarkDotNet.Attributes.Exporters;
 using System;