From 0907eadb55f59107489e3d59209cd57d6bb87778 Mon Sep 17 00:00:00 2001
From: Christian Kratky <christian.kratky@googlemail.com>
Date: Sat, 9 Sep 2017 21:50:55 +0200
Subject: [PATCH] Make string format optional if no trace listener is attached

---
 MQTTnet.Core/Diagnostics/MqttTrace.cs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/MQTTnet.Core/Diagnostics/MqttTrace.cs b/MQTTnet.Core/Diagnostics/MqttTrace.cs
index 86f5b45..c6104dc 100644
--- a/MQTTnet.Core/Diagnostics/MqttTrace.cs
+++ b/MQTTnet.Core/Diagnostics/MqttTrace.cs
@@ -38,7 +38,14 @@ namespace MQTTnet.Core.Diagnostics
 
         private static void Publish(string source, MqttTraceLevel traceLevel, Exception exception, string message)
         {
-            TraceMessagePublished?.Invoke(null, new MqttTraceMessagePublishedEventArgs(Environment.CurrentManagedThreadId, source, traceLevel, message, exception));
+            var handler = TraceMessagePublished;
+            if (handler == null)
+            {
+                return;
+            }
+
+            message = string.Format(message, 1);
+            handler.Invoke(null, new MqttTraceMessagePublishedEventArgs(Environment.CurrentManagedThreadId, source, traceLevel, message, exception));
         }
     }
 }