Delete unused file

src/DotNetCore.CAP/Serialization/StringSerializer.cs

@@ -1,21 +0,0 @@
-// Copyright (c) .NET Core Community. All rights reserved.
-// Licensed under the MIT License. See License.txt in the project root for license information.
-
-using DotNetCore.CAP.Messages;
-using Newtonsoft.Json;
-
-namespace DotNetCore.CAP.Serialization
-{
-    public class StringSerializer
-    {
-        public static string Serialize(Message message)
-        {
-            return JsonConvert.SerializeObject(message);
-        }
-
-        public static Message DeSerialize(string json)
-        {
-            return JsonConvert.DeserializeObject<Message>(json);
-        }
-    }
-}