Improve logger performance.

Source/MQTTnet/Diagnostics/IMqttNetLogger.cs

@@ -6,8 +6,8 @@ namespace MQTTnet.Diagnostics
     {
         event EventHandler<MqttNetLogMessagePublishedEventArgs> LogMessagePublished;
 
-        IMqttNetLogger CreateChildLogger(string source);
+        IMqttNetScopedLogger CreateScopedLogger(string source);
 
-        void Publish(MqttNetLogLevel logLevel, string message, object[] parameters, Exception exception);
+        void Publish(MqttNetLogLevel logLevel, string source, string message, object[] parameters, Exception exception);
     }
 }

Source/MQTTnet/Diagnostics/IMqttNetScopedLogger.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace MQTTnet.Diagnostics
+{
+    public interface IMqttNetScopedLogger
+    {
+        IMqttNetScopedLogger CreateScopedLogger(string source);
+
+        void Publish(MqttNetLogLevel logLevel, string message, object[] parameters, Exception exception);
+    }
+}

Source/MQTTnet/Diagnostics/MqttNetLogger.cs

@@ -7,14 +7,6 @@ namespace MQTTnet.Diagnostics
         readonly string _logId;
         readonly string _source;
 
-        readonly MqttNetLogger _parentLogger;
-
-        public MqttNetLogger(string source, string logId)
-        {
-            _source = source;
-            _logId = logId;
-        }
-
         public MqttNetLogger()
         {
         }
@@ -24,31 +16,23 @@ namespace MQTTnet.Diagnostics
             _logId = logId;
         }
 
-        MqttNetLogger(MqttNetLogger parentLogger, string logId, string source)
-        {
-            _parentLogger = parentLogger ?? throw new ArgumentNullException(nameof(parentLogger));
-            _source = source ?? throw new ArgumentNullException(nameof(source));
-
-            _logId = logId;
-        }
-
         public event EventHandler<MqttNetLogMessagePublishedEventArgs> LogMessagePublished;
 
         // TODO: Consider creating a LoggerFactory which will allow creating loggers. The logger factory will
         // be the only place which has the published event.
-        public IMqttNetLogger CreateChildLogger(string source)
+        public IMqttNetScopedLogger CreateScopedLogger(string source)
         {
             if (source is null) throw new ArgumentNullException(nameof(source));
 
-            return new MqttNetLogger(this, _logId, source);
+            return new MqttNetScopedLogger(this, source);
         }
 
-        public void Publish(MqttNetLogLevel level, string message, object[] parameters, Exception exception)
+        public void Publish(MqttNetLogLevel level, string source, string message, object[] parameters, Exception exception)
         {
             var hasLocalListeners = LogMessagePublished != null;
             var hasGlobalListeners = MqttNetGlobalLogger.HasListeners;
 
-            if (!hasLocalListeners && !hasGlobalListeners && _parentLogger == null)
+            if (!hasLocalListeners && !hasGlobalListeners)
             {
                 return;
             }
@@ -85,15 +69,6 @@ namespace MQTTnet.Diagnostics
             {
                 LogMessagePublished?.Invoke(this, new MqttNetLogMessagePublishedEventArgs(logMessage));
             }
-
-            _parentLogger?.Publish(logMessage);
-        }
-
-        void Publish(MqttNetLogMessage logMessage)
-        {
-            LogMessagePublished?.Invoke(this, new MqttNetLogMessagePublishedEventArgs(logMessage));
-
-            _parentLogger?.Publish(logMessage);
         }
     }
 }

Source/MQTTnet/Diagnostics/MqttNetLoggerExtensions.cs

@@ -1,35 +0,0 @@
-using System;
-
-namespace MQTTnet.Diagnostics
-{
-    public static class MqttNetLoggerExtensions
-    {
-        public static void Verbose(this IMqttNetLogger logger, string message, params object[] parameters)
-        {
-            if (logger is null) throw new ArgumentNullException(nameof(logger));
-
-            logger.Publish(MqttNetLogLevel.Verbose, message, parameters, null);
-        }
-
-        public static void Info(this IMqttNetLogger logger, string message, params object[] parameters)
-        {
-            if (logger is null) throw new ArgumentNullException(nameof(logger));
-
-            logger.Publish(MqttNetLogLevel.Info, message, parameters, null);
-        }
-
-        public static void Warning(this IMqttNetLogger logger, Exception exception, string message, params object[] parameters)
-        {
-            if (logger is null) throw new ArgumentNullException(nameof(logger));
-
-            logger.Publish(MqttNetLogLevel.Warning, message, parameters, exception);
-        }
-
-        public static void Error(this IMqttNetLogger logger, Exception exception, string message, params object[] parameters)
-        {
-            if (logger is null) throw new ArgumentNullException(nameof(logger));
-
-            logger.Publish(MqttNetLogLevel.Error, message, parameters, exception);
-        }
-    }
-}

Source/MQTTnet/Diagnostics/MqttNetScopedLogger.cs

@@ -0,0 +1,26 @@
+using System;
+
+namespace MQTTnet.Diagnostics
+{
+    public sealed class MqttNetScopedLogger : IMqttNetScopedLogger
+    {
+        readonly IMqttNetLogger _logger;
+        readonly string _source;
+
+        public MqttNetScopedLogger(IMqttNetLogger logger, string source)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _source = source ?? throw new ArgumentNullException(nameof(source));
+        }
+
+        public IMqttNetScopedLogger CreateScopedLogger(string source)
+        {
+            return new MqttNetScopedLogger(_logger, source);
+        }
+
+        public void Publish(MqttNetLogLevel logLevel, string message, object[] parameters, Exception exception)
+        {
+            _logger.Publish(logLevel, _source, message, parameters, exception);
+        }
+    }
+}

Source/MQTTnet/Diagnostics/MqttNetScopedLoggerExtensions.cs

@@ -0,0 +1,27 @@
+using System;
+
+namespace MQTTnet.Diagnostics
+{
+    public static class MqttNetScopedLoggerExtensions
+    {
+        public static void Verbose(this IMqttNetScopedLogger logger, string message, params object[] parameters)
+        {
+            logger.Publish(MqttNetLogLevel.Verbose, message, parameters, null);
+        }
+
+        public static void Info(this IMqttNetScopedLogger logger, string message, params object[] parameters)
+        {
+            logger.Publish(MqttNetLogLevel.Info, message, parameters, null);
+        }
+
+        public static void Warning(this IMqttNetScopedLogger logger, Exception exception, string message, params object[] parameters)
+        {
+            logger.Publish(MqttNetLogLevel.Warning, message, parameters, exception);
+        }
+
+        public static void Error(this IMqttNetScopedLogger logger, Exception exception, string message, params object[] parameters)
+        {
+            logger.Publish(MqttNetLogLevel.Error, message, parameters, exception);
+        }
+    }
+}