Adds MessagePack serialization for nucache

src/Umbraco.Web/PublishedCache/NuCache/DataSource/MsgPackContentNestedDataSerializer.cs

@@ -0,0 +1,42 @@
+using MessagePack;
+using System;
+
+namespace Umbraco.Web.PublishedCache.NuCache.DataSource
+{
+    internal class MsgPackContentNestedDataSerializer : IContentNestedDataSerializer
+    {
+        private MessagePackSerializerOptions _options;
+
+        public MsgPackContentNestedDataSerializer()
+        {
+            _options = MessagePack.Resolvers.ContractlessStandardResolver.Options.WithCompression(MessagePackCompression.Lz4BlockArray);
+        }
+
+        public string ToJson(string serialized)
+        {
+            var bin = Convert.FromBase64String(serialized);
+            var json = MessagePackSerializer.ConvertToJson(bin, _options);
+            return json;
+        }
+
+        // TODO: Instead of returning base64 it would be more ideal to avoid that translation entirely and just store/retrieve raw bytes
+
+        // TODO: We need to write tests to serialize/deserialize between either of these serializers to ensure we end up with the same object
+        // i think this one is a bit quirky so far :)
+
+        public ContentNestedData Deserialize(string data)
+        {
+            var bin = Convert.FromBase64String(data);
+            var obj = MessagePackSerializer.Deserialize<ContentNestedData>(bin, _options);
+            return obj;
+        }
+
+        public string Serialize(ContentNestedData nestedData)
+        {            
+            var bin = MessagePackSerializer.Serialize(
+              nestedData,
+              _options);
+            return Convert.ToBase64String(bin);
+        }
+    }
+}