added message class and added references to server and client projects

Message/Message.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
+  </ItemGroup>
+
+</Project>

Message/Program.cs

@@ -0,0 +1,34 @@
+using Newtonsoft.Json;
+using System;
+
+namespace Message
+{
+    public class Message
+    {
+        public string Identifier
+        {
+            get;set;
+        }
+
+        public string Payload
+        {
+            get;set;
+        }
+
+        public Message(string identifier, string payload)
+        {
+            this.Identifier = identifier;
+            this.Payload = payload;
+        }
+
+        public string Serialize()
+        {
+            return JsonConvert.SerializeObject(this);
+        }
+
+        public static Message Deserialize(string json)
+        {
+            return (Message)JsonConvert.DeserializeObject(json);
+        }
+    }
+}