Add .NET Core 2.1 versions

worker/dotnet/Worker/Messaging/Messages/Events/VoteCastEvent.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Worker.Messaging.Messages
+{
+    public class VoteCastEvent : Message
+    {
+        public override string Subject { get { return MessageSubject; } }
+
+        public string VoterId {get; set;}
+
+        public string Vote {get; set; }
+
+         public static string MessageSubject = "events.vote.votecast";
+    }
+}

worker/dotnet/Worker/Messaging/Messages/Message.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace Worker.Messaging.Messages
+{
+    public abstract class Message
+    {
+        public string CorrelationId { get; set; }  
+        
+        public abstract string Subject { get; }      
+
+        public Message()
+        {
+            CorrelationId = Guid.NewGuid().ToString();
+        }
+    }
+}