Pass session item to several more event handers.

Source/MQTTnet/Server/Events/ApplicationMessageNotConsumedEventArgs.cs

@@ -8,14 +8,20 @@ namespace MQTTnet.Server
 {
     public sealed class ApplicationMessageNotConsumedEventArgs : EventArgs
     {
+        public ApplicationMessageNotConsumedEventArgs(MqttApplicationMessage applicationMessage, string senderId)
+        {
+            ApplicationMessage = applicationMessage ?? throw new ArgumentNullException(nameof(applicationMessage));
+            SenderId = senderId;
+        }
+
         /// <summary>
         ///     Gets the application message which was not consumed by any client.
         /// </summary>
-        public MqttApplicationMessage ApplicationMessage { get; internal set; }
+        public MqttApplicationMessage ApplicationMessage { get; }
 
         /// <summary>
         ///     Gets the ID of the client which has sent the affected application message.
         /// </summary>
-        public string SenderId { get; internal set; }
+        public string SenderId { get; }
     }
 }
\ No newline at end of file

Source/MQTTnet/Server/Events/ClientConnectedEventArgs.cs

@@ -3,31 +3,46 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections;
 using MQTTnet.Formatter;
 
 namespace MQTTnet.Server
 {
     public sealed class ClientConnectedEventArgs : EventArgs
     {
+        public ClientConnectedEventArgs(string clientId, string userName, MqttProtocolVersion protocolVersion, string endpoint, IDictionary sessionItems)
+        {
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            UserName = userName;
+            ProtocolVersion = protocolVersion;
+            Endpoint = endpoint;
+            SessionItems = sessionItems ?? throw new ArgumentNullException(nameof(sessionItems));
+        }
+
+        /// <summary>
+        ///     Gets the client identifier of the connected client.
+        ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        /// </summary>
+        public string ClientId { get; }
+
         /// <summary>
-        /// Gets the client identifier of the connected client.
-        /// Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        ///     Gets the endpoint of the connected client.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public string Endpoint { get; }
 
         /// <summary>
-        /// Gets the user name of the connected client.
+        ///     Gets the protocol version which is used by the connected client.
         /// </summary>
-        public string UserName { get; internal set; }
+        public MqttProtocolVersion ProtocolVersion { get; }
 
         /// <summary>
-        /// Gets the protocol version which is used by the connected client.
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public MqttProtocolVersion ProtocolVersion { get; internal set; }
+        public IDictionary SessionItems { get; }
 
         /// <summary>
-        /// Gets the endpoint of the connected client.
+        ///     Gets the user name of the connected client.
         /// </summary>
-        public string Endpoint { get; internal set; }
+        public string UserName { get; }
     }
-}
+}
\ No newline at end of file

Source/MQTTnet/Server/Events/ClientDisconnectedEventArgs.cs

@@ -3,19 +3,33 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections;
 
 namespace MQTTnet.Server
 {
     public sealed class ClientDisconnectedEventArgs : EventArgs
     {
+        public ClientDisconnectedEventArgs(string clientId, MqttClientDisconnectType disconnectType, string endpoint, IDictionary sessionItems)
+        {
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            DisconnectType = disconnectType;
+            Endpoint = endpoint;
+            SessionItems = sessionItems ?? throw new ArgumentNullException(nameof(sessionItems));
+        }
+
         /// <summary>
-        /// Gets the client identifier.
-        /// Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        ///     Gets the client identifier.
+        ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public string ClientId { get; }
+
+        public MqttClientDisconnectType DisconnectType { get; }
 
-        public MqttClientDisconnectType DisconnectType { get; internal set; }
+        public string Endpoint { get; }
 
-        public string Endpoint { get; internal set; }
+        /// <summary>
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
+        /// </summary>
+        public IDictionary SessionItems { get; }
     }
-}
+}
\ No newline at end of file

Source/MQTTnet/Server/Events/ClientSubscribedTopicEventArgs.cs

@@ -3,22 +3,35 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections;
 using MQTTnet.Packets;
 
 namespace MQTTnet.Server
 {
     public sealed class ClientSubscribedTopicEventArgs : EventArgs
     {
+        public ClientSubscribedTopicEventArgs(string clientId, MqttTopicFilter topicFilter, IDictionary sessionItems)
+        {
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            TopicFilter = topicFilter ?? throw new ArgumentNullException(nameof(topicFilter));
+            SessionItems = sessionItems ?? throw new ArgumentNullException(nameof(sessionItems));
+        }
+
+        /// <summary>
+        ///     Gets the client identifier.
+        ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        /// </summary>
+        public string ClientId { get; }
+
         /// <summary>
-        /// Gets the client identifier.
-        /// Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public IDictionary SessionItems { get; }
 
         /// <summary>
-        /// Gets the topic filter.
-        /// The topic filter can contain topics and wildcards.
+        ///     Gets the topic filter.
+        ///     The topic filter can contain topics and wildcards.
         /// </summary>
-        public MqttTopicFilter TopicFilter { get; internal set; }
+        public MqttTopicFilter TopicFilter { get; }
     }
-}
+}
\ No newline at end of file

Source/MQTTnet/Server/Events/ClientUnsubscribedTopicEventArgs.cs

@@ -3,21 +3,34 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections;
 
 namespace MQTTnet.Server
 {
     public sealed class ClientUnsubscribedTopicEventArgs : EventArgs
     {
+        public ClientUnsubscribedTopicEventArgs(string clientId, string topicFilter, IDictionary sessionItems)
+        {
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            TopicFilter = topicFilter ?? throw new ArgumentNullException(nameof(topicFilter));
+            SessionItems = sessionItems ?? throw new ArgumentNullException(nameof(sessionItems));
+        }
+
+        /// <summary>
+        ///     Gets the client identifier.
+        ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        /// </summary>
+        public string ClientId { get; }
+
         /// <summary>
-        /// Gets the client identifier.
-        /// Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public IDictionary SessionItems { get; }
 
         /// <summary>
-        /// Gets or sets the topic filter.
-        /// The topic filter can contain topics and wildcards.
+        ///     Gets or sets the topic filter.
+        ///     The topic filter can contain topics and wildcards.
         /// </summary>
-        public string TopicFilter { get; internal set; }
+        public string TopicFilter { get; }
     }
-}
+}
\ No newline at end of file

Source/MQTTnet/Server/Events/InterceptingPacketEventArgs.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections;
 using System.Threading;
 using MQTTnet.Packets;
 
@@ -10,30 +11,44 @@ namespace MQTTnet.Server
 {
     public sealed class InterceptingPacketEventArgs : EventArgs
     {
+        public InterceptingPacketEventArgs(CancellationToken cancellationToken, string clientId, string endpoint, MqttPacket packet, IDictionary sessionItems)
+        {
+            CancellationToken = cancellationToken;
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            Endpoint = endpoint;
+            Packet = packet ?? throw new ArgumentNullException(nameof(packet));
+            SessionItems = sessionItems;
+        }
+
         /// <summary>
-        /// Gets the client ID which has sent the packet or will receive the packet.
+        ///     Gets the cancellation token from the connection managing thread.
+        ///     Use this in further event processing.
         /// </summary>
-        public string ClientId { get; internal set; }
-        
+        public CancellationToken CancellationToken { get; }
+
         /// <summary>
-        /// Gets the endpoint of the sending or receiving client.
+        ///     Gets the client ID which has sent the packet or will receive the packet.
         /// </summary>
-        public string Endpoint { get; internal set; }
-        
+        public string ClientId { get; }
+
         /// <summary>
-        /// Gets or sets the MQTT packet which was received or will be sent.
+        ///     Gets the endpoint of the sending or receiving client.
+        /// </summary>
+        public string Endpoint { get; }
+
+        /// <summary>
+        ///     Gets or sets the MQTT packet which was received or will be sent.
         /// </summary>
         public MqttPacket Packet { get; set; }
 
         /// <summary>
-        /// Gets or sets whether the packet should be processed or not.
+        ///     Gets or sets whether the packet should be processed or not.
         /// </summary>
         public bool ProcessPacket { get; set; } = true;
-        
+
         /// <summary>
-        /// Gets the cancellation token from the connection managing thread.
-        /// Use this in further event processing.
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public CancellationToken CancellationToken { get; internal set; }
+        public IDictionary SessionItems { get; }
     }
 }
\ No newline at end of file

Source/MQTTnet/Server/Events/InterceptingPublishEventArgs.cs

@@ -10,18 +10,26 @@ namespace MQTTnet.Server
 {
     public sealed class InterceptingPublishEventArgs : EventArgs
     {
+        public InterceptingPublishEventArgs(MqttApplicationMessage applicationMessage, CancellationToken cancellationToken, string clientId, IDictionary sessionItems)
+        {
+            ApplicationMessage = applicationMessage ?? throw new ArgumentNullException(nameof(applicationMessage));
+            CancellationToken = cancellationToken;
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            SessionItems = sessionItems ?? throw new ArgumentNullException(nameof(sessionItems));
+        }
+
         public MqttApplicationMessage ApplicationMessage { get; set; }
 
         /// <summary>
         ///     Gets the cancellation token which can indicate that the client connection gets down.
         /// </summary>
-        public CancellationToken CancellationToken { get; internal set; }
+        public CancellationToken CancellationToken { get; }
 
         /// <summary>
         ///     Gets the client identifier.
         ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public string ClientId { get; }
 
         public bool CloseConnection { get; set; }
 
@@ -38,6 +46,6 @@ namespace MQTTnet.Server
         /// <summary>
         ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public IDictionary SessionItems { get; internal set; }
+        public IDictionary SessionItems { get; }
     }
 }
\ No newline at end of file

Source/MQTTnet/Server/Events/InterceptingSubscriptionEventArgs.cs

@@ -12,16 +12,28 @@ namespace MQTTnet.Server
 {
     public sealed class InterceptingSubscriptionEventArgs : EventArgs
     {
+        public InterceptingSubscriptionEventArgs(
+            CancellationToken cancellationToken,
+            string clientId,
+            MqttSessionStatus session,
+            MqttTopicFilter topicFilter)
+        {
+            CancellationToken = cancellationToken;
+            ClientId = clientId;
+            Session = session;
+            TopicFilter = topicFilter;
+        }
+
         /// <summary>
         ///     Gets the cancellation token which can indicate that the client connection gets down.
         /// </summary>
-        public CancellationToken CancellationToken { get; internal set; }
+        public CancellationToken CancellationToken { get; }
 
         /// <summary>
         ///     Gets the client identifier.
         ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public string ClientId { get; }
 
         /// <summary>
         ///     Gets or sets whether the broker should close the client connection.
@@ -48,12 +60,12 @@ namespace MQTTnet.Server
         /// <summary>
         ///     Gets the current client session.
         /// </summary>
-        public MqttSessionStatus Session { get; internal set; }
+        public MqttSessionStatus Session { get; }
 
         /// <summary>
         ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public IDictionary SessionItems { get; internal set; }
+        public IDictionary SessionItems => Session.Items;
 
         /// <summary>
         ///     Gets or sets the topic filter.

Source/MQTTnet/Server/Events/InterceptingUnsubscriptionEventArgs.cs

@@ -10,16 +10,24 @@ namespace MQTTnet.Server
 {
     public sealed class InterceptingUnsubscriptionEventArgs : EventArgs
     {
+        public InterceptingUnsubscriptionEventArgs(CancellationToken cancellationToken, string clientId, IDictionary sessionItems, string topic)
+        {
+            CancellationToken = cancellationToken;
+            ClientId = clientId;
+            SessionItems = sessionItems;
+            Topic = topic;
+        }
+
         /// <summary>
         ///     Gets the cancellation token which can indicate that the client connection gets down.
         /// </summary>
-        public CancellationToken CancellationToken { get; internal set; }
+        public CancellationToken CancellationToken { get; }
 
         /// <summary>
         ///     Gets the client identifier.
         ///     Hint: This identifier needs to be unique over all used clients / devices on the broker to avoid connection issues.
         /// </summary>
-        public string ClientId { get; internal set; }
+        public string ClientId { get; }
 
         /// <summary>
         ///     Gets or sets whether the broker should close the client connection.
@@ -41,7 +49,7 @@ namespace MQTTnet.Server
         /// <summary>
         ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public IDictionary SessionItems { get; internal set; }
+        public IDictionary SessionItems { get; }
 
         /// <summary>
         ///     Gets or sets the MQTT topic.
@@ -50,6 +58,6 @@ namespace MQTTnet.Server
         ///     The topic consists of one or more topic levels. Each topic level is separated by a forward slash (topic level
         ///     separator).
         /// </summary>
-        public string Topic { get; internal set; }
+        public string Topic { get; }
     }
 }
\ No newline at end of file

Source/MQTTnet/Server/Events/RetainedMessageChangedEventArgs.cs

@@ -9,10 +9,17 @@ namespace MQTTnet.Server
 {
     public sealed class RetainedMessageChangedEventArgs : EventArgs
     {
-        public string ClientId { get; internal set; }
-        
-        public MqttApplicationMessage ChangedRetainedMessage { get; internal set; }
-        
-        public List<MqttApplicationMessage> StoredRetainedMessages { get; internal set; }
+        public RetainedMessageChangedEventArgs(string clientId, MqttApplicationMessage changedRetainedMessage, List<MqttApplicationMessage> storedRetainedMessages)
+        {
+            ClientId = clientId ?? throw new ArgumentNullException(nameof(clientId));
+            ChangedRetainedMessage = changedRetainedMessage ?? throw new ArgumentNullException(nameof(changedRetainedMessage));
+            StoredRetainedMessages = storedRetainedMessages ?? throw new ArgumentNullException(nameof(storedRetainedMessages));
+        }
+
+        public MqttApplicationMessage ChangedRetainedMessage { get; }
+
+        public string ClientId { get; }
+
+        public List<MqttApplicationMessage> StoredRetainedMessages { get; }
     }
 }
\ No newline at end of file

Source/MQTTnet/Server/Events/SessionDeletedEventArgs.cs

@@ -3,14 +3,26 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections;
 
 namespace MQTTnet.Server
 {
     public sealed class SessionDeletedEventArgs : EventArgs
     {
+        public SessionDeletedEventArgs(string id, IDictionary sessionItems)
+        {
+            Id = id ?? throw new ArgumentNullException(nameof(id));
+            SessionItems = sessionItems ?? throw new ArgumentNullException(nameof(sessionItems));
+        }
+
+        /// <summary>
+        ///     Gets the ID of the session.
+        /// </summary>
+        public string Id { get; }
+
         /// <summary>
-        /// Gets the ID of the session.
+        ///     Gets or sets a key/value collection that can be used to share data within the scope of this session.
         /// </summary>
-        public string Id { get; internal set; }
+        public IDictionary SessionItems { get; }
     }
 }
\ No newline at end of file

Source/MQTTnet/Server/Internal/MqttClient.cs

@@ -160,15 +160,8 @@ namespace MQTTnet.Server
             {
                 return packet;
             }
-            
-            var interceptingPacketEventArgs = new InterceptingPacketEventArgs
-            {
-                ClientId = Id,
-                Endpoint = Endpoint,
-                Packet = packet,
-                CancellationToken = cancellationToken
-            };
-            
+
+            var interceptingPacketEventArgs = new InterceptingPacketEventArgs(cancellationToken, Id, Endpoint, packet, Session.Items);
             await _eventContainer.InterceptingOutboundPacketEvent.InvokeAsync(interceptingPacketEventArgs).ConfigureAwait(false);
                 
             if (!interceptingPacketEventArgs.ProcessPacket || packet == null)
@@ -200,14 +193,7 @@ namespace MQTTnet.Server
                     
                     if (_eventContainer.InterceptingInboundPacketEvent.HasHandlers)
                     {
-                        var interceptingPacketEventArgs = new InterceptingPacketEventArgs
-                        {
-                            ClientId = Id,
-                            Endpoint = Endpoint,
-                            Packet = packet,
-                            CancellationToken = cancellationToken
-                        };
-                    
+                        var interceptingPacketEventArgs = new InterceptingPacketEventArgs(cancellationToken, Id, Endpoint, packet, Session.Items);
                         await _eventContainer.InterceptingInboundPacketEvent.InvokeAsync(interceptingPacketEventArgs).ConfigureAwait(false);
                         packet = interceptingPacketEventArgs.Packet;
                         processPacket = interceptingPacketEventArgs.ProcessPacket;
@@ -428,16 +414,7 @@ namespace MQTTnet.Server
             
             if (_eventContainer.InterceptingPublishEvent.HasHandlers)
             {
-                interceptingPublishEventArgs = new InterceptingPublishEventArgs
-                {
-                    ClientId = Id,
-                    ApplicationMessage = applicationMessage,
-                    SessionItems = Session.Items,
-                    ProcessPublish = true,
-                    CloseConnection = false,
-                    CancellationToken = cancellationToken
-                };
-
+                interceptingPublishEventArgs = new InterceptingPublishEventArgs(applicationMessage, cancellationToken, Id, Session.Items);
                 if (string.IsNullOrEmpty(interceptingPublishEventArgs.ApplicationMessage.Topic))
                 {
                     // This can happen if a topic alias us used but the topic is

Source/MQTTnet/Server/Internal/MqttClientSessionsManager.cs

@@ -109,13 +109,9 @@ namespace MQTTnet.Server
 
             try
             {
-                if (_eventContainer.SessionDeletedEvent.HasHandlers)
+                if (_eventContainer.SessionDeletedEvent.HasHandlers && session != null)
                 {
-                    var eventArgs = new SessionDeletedEventArgs
-                    {
-                        Id = session?.Id
-                    };
-
+                    var eventArgs = new SessionDeletedEventArgs(clientId, session.Items);
                     await _eventContainer.SessionDeletedEvent.TryInvokeAsync(eventArgs, _logger).ConfigureAwait(false);
                 }
             }
@@ -295,13 +291,12 @@ namespace MQTTnet.Server
 
                 if (_eventContainer.ClientConnectedEvent.HasHandlers)
                 {
-                    var eventArgs = new ClientConnectedEventArgs
-                    {
-                        ClientId = connectPacket.ClientId,
-                        UserName = connectPacket.Username,
-                        ProtocolVersion = channelAdapter.PacketFormatterAdapter.ProtocolVersion,
-                        Endpoint = channelAdapter.Endpoint
-                    };
+                    var eventArgs = new ClientConnectedEventArgs(
+                        connectPacket.ClientId,
+                        connectPacket.Username,
+                        channelAdapter.PacketFormatterAdapter.ProtocolVersion,
+                        channelAdapter.Endpoint,
+                        client.Session.Items);
 
                     await _eventContainer.ClientConnectedEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
                 }
@@ -340,12 +335,8 @@ namespace MQTTnet.Server
 
                     if (client.Id != null && !client.IsTakenOver && _eventContainer.ClientDisconnectedEvent.HasHandlers)
                     {
-                        var eventArgs = new ClientDisconnectedEventArgs
-                        {
-                            ClientId = client.Id,
-                            DisconnectType = client.IsCleanDisconnect ? MqttClientDisconnectType.Clean : MqttClientDisconnectType.NotClean,
-                            Endpoint = endpoint
-                        };
+                        var disconnectType = client.IsCleanDisconnect ? MqttClientDisconnectType.Clean : MqttClientDisconnectType.NotClean;
+                        var eventArgs = new ClientDisconnectedEventArgs(client.Id, disconnectType, endpoint, client.Session.Items);
 
                         await _eventContainer.ClientDisconnectedEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
                     }
@@ -533,13 +524,7 @@ namespace MQTTnet.Server
 
                     if (_eventContainer.ClientConnectedEvent.HasHandlers)
                     {
-                        var eventArgs = new ClientDisconnectedEventArgs
-                        {
-                            ClientId = existing.Id,
-                            DisconnectType = MqttClientDisconnectType.Takeover,
-                            Endpoint = existing.Endpoint
-                        };
-
+                        var eventArgs = new ClientDisconnectedEventArgs(existing.Id, MqttClientDisconnectType.Takeover, existing.Endpoint, existing.Session.Items);
                         await _eventContainer.ClientDisconnectedEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
                     }
                 }
@@ -572,12 +557,7 @@ namespace MQTTnet.Server
                 return;
             }
 
-            var eventArgs = new ApplicationMessageNotConsumedEventArgs
-            {
-                ApplicationMessage = applicationMessage,
-                SenderId = senderId
-            };
-
+            var eventArgs = new ApplicationMessageNotConsumedEventArgs(applicationMessage, senderId);
             await _eventContainer.ApplicationMessageNotConsumedEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
         }
 

Source/MQTTnet/Server/Internal/MqttClientSubscriptionsManager.cs

@@ -217,12 +217,7 @@ namespace MQTTnet.Server
             {
                 foreach (var finalTopicFilter in finalTopicFilters)
                 {
-                    var eventArgs = new ClientSubscribedTopicEventArgs
-                    {
-                        ClientId = _session.Id,
-                        TopicFilter = finalTopicFilter
-                    };
-
+                    var eventArgs = new ClientSubscribedTopicEventArgs(_session.Id, finalTopicFilter, _session.Items);
                     await _eventContainer.ClientSubscribedTopicEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
                 }
             }
@@ -312,12 +307,7 @@ namespace MQTTnet.Server
             {
                 foreach (var topicFilter in unsubscribePacket.TopicFilters)
                 {
-                    var eventArgs = new ClientUnsubscribedTopicEventArgs
-                    {
-                        ClientId = _session.Id,
-                        TopicFilter = topicFilter
-                    };
-
+                    var eventArgs = new ClientUnsubscribedTopicEventArgs(_session.Id, topicFilter, _session.Items);
                     await _eventContainer.ClientUnsubscribedTopicEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
                 }
             }
@@ -472,14 +462,7 @@ namespace MQTTnet.Server
 
         async Task<InterceptingSubscriptionEventArgs> InterceptSubscribe(MqttTopicFilter topicFilter, CancellationToken cancellationToken)
         {
-            var eventArgs = new InterceptingSubscriptionEventArgs
-            {
-                ClientId = _session.Id,
-                TopicFilter = topicFilter,
-                SessionItems = _session.Items,
-                Session = new MqttSessionStatus(_session),
-                CancellationToken = cancellationToken
-            };
+            var eventArgs = new InterceptingSubscriptionEventArgs(cancellationToken, _session.Id, new MqttSessionStatus(_session), topicFilter);
 
             if (topicFilter.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtMostOnce)
             {
@@ -508,13 +491,7 @@ namespace MQTTnet.Server
 
         async Task<InterceptingUnsubscriptionEventArgs> InterceptUnsubscribe(string topicFilter, MqttSubscription mqttSubscription, CancellationToken cancellationToken)
         {
-            var clientUnsubscribingTopicEventArgs = new InterceptingUnsubscriptionEventArgs
-            {
-                ClientId = _session.Id,
-                Topic = topicFilter,
-                SessionItems = _session.Items,
-                CancellationToken = cancellationToken
-            };
+            var clientUnsubscribingTopicEventArgs = new InterceptingUnsubscriptionEventArgs(cancellationToken, topicFilter, _session.Items, topicFilter);
 
             if (mqttSubscription == null)
             {

Source/MQTTnet/Server/Internal/MqttRetainedMessagesManager.cs

@@ -105,13 +105,7 @@ namespace MQTTnet.Server
                 {
                     using (await _storageAccessLock.WaitAsync(CancellationToken.None).ConfigureAwait(false))
                     {
-                        var eventArgs = new RetainedMessageChangedEventArgs
-                        {
-                            ClientId = clientId,
-                            ChangedRetainedMessage = applicationMessage,
-                            StoredRetainedMessages = messagesForSave
-                        };
-                        
+                        var eventArgs = new RetainedMessageChangedEventArgs(clientId, applicationMessage, messagesForSave);
                         await _eventContainer.RetainedMessageChangedEvent.InvokeAsync(eventArgs).ConfigureAwait(false);
                     }
                 }