Fix logging issues.

Source/MQTTnet.Server/Logging/MqttNetLoggerWrapper.cs

@@ -7,7 +7,7 @@ namespace MQTTnet.Server.Logging
 {
     public class MqttNetLoggerWrapper : IMqttNetLogger
     {
-        private readonly ILogger<MqttServer> _logger;
+        readonly ILogger<MqttServer> _logger;
 
         public MqttNetLoggerWrapper(ILogger<MqttServer> logger)
         {
@@ -16,7 +16,7 @@ namespace MQTTnet.Server.Logging
 
         public event EventHandler<MqttNetLogMessagePublishedEventArgs> LogMessagePublished;
 
-        public IMqttNetLogger CreateChildLogger(string source = null)
+        public IMqttNetLogger CreateChildLogger(string source)
         {
             return new MqttNetLogger(source);
         }

Source/MQTTnet/Diagnostics/MqttNetLogger.cs

@@ -9,7 +9,7 @@ namespace MQTTnet.Diagnostics
 
         readonly MqttNetLogger _parentLogger;
 
-        public MqttNetLogger(string source, string logId = null)
+        public MqttNetLogger(string source, string logId)
         {
             _source = source;
             _logId = logId;
@@ -19,6 +19,11 @@ namespace MQTTnet.Diagnostics
         {
         }
 
+        public MqttNetLogger(string logId)
+        {
+            _logId = logId;
+        }
+
         MqttNetLogger(MqttNetLogger parentLogger, string logId, string source)
         {
             _parentLogger = parentLogger ?? throw new ArgumentNullException(nameof(parentLogger));

Source/MQTTnet/MqttFactory.cs

@@ -13,7 +13,7 @@ namespace MQTTnet
     {
         IMqttClientAdapterFactory _clientAdapterFactory = new MqttClientAdapterFactory();
 
-        public MqttFactory() : this(new MqttNetLogger(null, null))
+        public MqttFactory() : this(new MqttNetLogger())
         {
         }
 

Tests/MQTTnet.Benchmarks/LoggerBenchmark.cs

@@ -16,7 +16,7 @@ namespace MQTTnet.Benchmarks
         [GlobalSetup]
         public void Setup()
         {
-            _logger = new MqttNetLogger("1");
+            _logger = new MqttNetLogger();
             _childLogger = _logger.CreateChildLogger("child");
 
             MqttNetGlobalLogger.LogMessagePublished += OnLogMessagePublished;

Tests/MQTTnet.Core.Tests/MqttFactory_Tests.cs

@@ -24,7 +24,7 @@ namespace MQTTnet.Tests
             //var globalLogCount = 0;
             var localLogCount = 0;
 
-            var logger = new MqttNetLogger(logId);
+            var logger = new MqttNetLogger(null, logId);
 
             // TODO: This is commented out because it is affected by other tests.
             //// we have a theoretical bug here if a concurrent test is also logging

Tests/MQTTnet.Core.Tests/MqttNetLogger_Tests.cs

@@ -46,5 +46,22 @@ namespace MQTTnet.Tests
 
             Assert.AreEqual(4, logMessagesCount);
         }
+
+        [TestMethod]
+        public void Set_Custom_Log_ID()
+        {
+            var logger = new MqttNetLogger(null, "logId");
+            var childLogger = logger.CreateChildLogger("Source1");
+
+            logger.LogMessagePublished += (s, e) =>
+            {
+                Assert.AreEqual("logId", e.LogMessage.LogId);
+            };
+
+            childLogger.Verbose("Verbose");
+            childLogger.Info("Info");
+            childLogger.Warning(null, "Warning");
+            childLogger.Error(null, "Error");
+        }
     }
 }