From 6adf7096ec3a9da627bf5768e87b4c816d8638dc Mon Sep 17 00:00:00 2001
From: SeppPenner <HansM2013@gmx.de>
Date: Fri, 12 Jun 2020 20:25:51 +0200
Subject: [PATCH] Updated client sessions manager to handle the delivery count
 for the handler correctly.

---
 Source/MQTTnet/Server/MqttClientSession.cs         | 6 ++++--
 Source/MQTTnet/Server/MqttClientSessionsManager.cs | 7 +++++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/Source/MQTTnet/Server/MqttClientSession.cs b/Source/MQTTnet/Server/MqttClientSession.cs
index c7d2e50d..c6c3e0ef 100644
--- a/Source/MQTTnet/Server/MqttClientSession.cs
+++ b/Source/MQTTnet/Server/MqttClientSession.cs
@@ -46,17 +46,19 @@ namespace MQTTnet.Server
         /// </summary>
         public IDictionary<object, object> Items { get; }
 
-        public void EnqueueApplicationMessage(MqttApplicationMessage applicationMessage, string senderClientId, bool isRetainedApplicationMessage)
+        public bool EnqueueApplicationMessage(MqttApplicationMessage applicationMessage, string senderClientId, bool isRetainedApplicationMessage)
         {
             var checkSubscriptionsResult = SubscriptionsManager.CheckSubscriptions(applicationMessage.Topic, applicationMessage.QualityOfServiceLevel);
             if (!checkSubscriptionsResult.IsSubscribed)
             {
-                return;
+                return true;
             }
 
             _logger.Verbose("Queued application message with topic '{0}' (ClientId: {1}).", applicationMessage.Topic, ClientId);
 
             ApplicationMessagesQueue.Enqueue(applicationMessage, senderClientId, checkSubscriptionsResult.QualityOfServiceLevel, isRetainedApplicationMessage);
+
+            return false;
         }
 
         public async Task SubscribeAsync(ICollection<MqttTopicFilter> topicFilters)
diff --git a/Source/MQTTnet/Server/MqttClientSessionsManager.cs b/Source/MQTTnet/Server/MqttClientSessionsManager.cs
index d27a366f..8a34f7b1 100644
--- a/Source/MQTTnet/Server/MqttClientSessionsManager.cs
+++ b/Source/MQTTnet/Server/MqttClientSessionsManager.cs
@@ -228,12 +228,15 @@ namespace MQTTnet.Server
 
                 foreach (var clientSession in _sessions.Values)
                 {
-                    clientSession.EnqueueApplicationMessage(
+                    var isSubscribed = clientSession.EnqueueApplicationMessage(
                         applicationMessage,
                         sender?.ClientId,
                         false);
 
-                    deliveryCount++;
+                    if (isSubscribed)
+                    {
+                        deliveryCount++;
+                    }
                 }
 
                 if (deliveryCount == 0)