Add connack properties to authenticate result.

Build/MQTTnet.nuspec

@@ -13,6 +13,8 @@
     <releaseNotes>
 * [Core] Fixed issues in MQTTv5 message encoding and decoding.
 * [Client] Added support for extended authentication exchange.
+* [Client] Exposed MQTTv5 CONNACK values to client.
+* [Client] Added _MqttClientSubscribeOptionsBuilder_.
     </releaseNotes>
     <copyright>Copyright Christian Kratky 2016-2019</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 

Source/MQTTnet/Client/Connecting/MqttClientAuthenticateResult.cs

@@ -1,9 +1,45 @@
-namespace MQTTnet.Client.Connecting
+using System.Collections.Generic;
+using MQTTnet.Packets;
+
+namespace MQTTnet.Client.Connecting
 {
+    // TODO: Consider renaming this to _MqttClientConnectResult_
     public class MqttClientAuthenticateResult
     {
+        public MqttClientConnectResultCode ResultCode { get; set; }
+
         public bool IsSessionPresent { get; set; }
 
-        public MqttClientConnectResultCode ResultCode { get; set; }
+        public bool? WildcardSubscriptionAvailable { get; set; }
+
+        public bool? RetainAvailable { get; set; }
+
+        public string AssignedClientIdentifier { get; set; }
+
+        public string AuthenticationMethod { get; set; }
+
+        public byte[] AuthenticationData { get; set; }
+
+        public uint? MaximumPacketSize { get; set; }
+
+        public string ReasonString { get; set; }
+
+        public ushort? ReceiveMaximum { get; set; }
+
+        public string ResponseInformation { get; set; }
+
+        public ushort? TopicAliasMaximum { get; set; }
+
+        public string ServerReference { get; set; }
+
+        public ushort? ServerKeepAlive { get; set; }
+
+        public uint? SessionExpiryInterval { get; set; }
+
+        public bool? SubscriptionIdentifiersAvailable { get; set; }
+
+        public bool? SharedSubscriptionAvailable { get; set; }
+
+        public List<MqttUserProperty> UserProperties { get; set; }
     }
 }