From c20142671f60a5f86c4a0a21018bee005cff77fe Mon Sep 17 00:00:00 2001
From: SeppPenner <HansM2013@gmx.de>
Date: Wed, 10 Jun 2020 11:52:55 +0200
Subject: [PATCH] MQTTnet: Adjusted UndeliveredMessageInterceptor handler to
 return if it's null instead of throwing an exception.

---
 Source/MQTTnet/Server/MqttClientSessionsManager.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Source/MQTTnet/Server/MqttClientSessionsManager.cs b/Source/MQTTnet/Server/MqttClientSessionsManager.cs
index 8be714d1..456636a2 100644
--- a/Source/MQTTnet/Server/MqttClientSessionsManager.cs
+++ b/Source/MQTTnet/Server/MqttClientSessionsManager.cs
@@ -238,7 +238,7 @@ namespace MQTTnet.Server
                 {
                     if (_options.UndeliveredMessageInterceptor == null)
                     {
-                        throw new OperationCanceledException(nameof(_options.UndeliveredMessageInterceptor));
+                        return;
                     }
 
                     await _options.UndeliveredMessageInterceptor.InterceptApplicationMessagePublishAsync(new MqttApplicationMessageInterceptorContext(sender?.ClientId, sender?.Session?.Items, applicationMessage));