Add migration doc samples

Author: sierpinskid

…owLevelClient/ExtraData/UserObjectDTO.cs …lient/ExtraData/UserObjectInternalDTO.csAssets/Plugins/StreamChat/Core/LowLevelClient/ExtraData/UserObjectDTO.cs renamed to Assets/Plugins/StreamChat/Core/LowLevelClient/ExtraData/UserObjectInternalDTO.cs Assets/Plugins/StreamChat/Core/LowLevelClient/ExtraData/UserObjectDTO.cs renamed to Assets/Plugins/StreamChat/Core/LowLevelClient/ExtraData/UserObjectInternalDTO.cs

@@ -0,0 +1,100 @@
+using StreamChat.Core.Models;
+
+namespace StreamChat.Samples
+{
+    internal class CodeMigrationTo5x
+    {
+        internal void VariableDeclarationAndAssignment()
+        {
+            // Old (enum)
+            //StreamMessageType messageType = StreamMessageType.Regular;
+
+            // New (struct)
+            StreamMessageType messageType = StreamMessageType.Regular;
+        }
+        
+        internal void MethodParametersAndAssignment()
+        {
+            // Old (enum)
+            // public void ProcessMessage(StreamMessageType type)
+            // {
+            //     
+            // }
+
+            // New (struct)
+            // public void ProcessMessage(StreamMessageType type)
+            // {
+            //
+            // }
+        }
+        
+        // New (struct)
+        public void ProcessMessage(StreamMessageType type)
+        {
+            
+        }
+
+        internal void Equality()
+        {
+            StreamMessageType messageType = StreamMessageType.Regular;
+            
+            // Old (enum)
+            if (messageType == StreamMessageType.Regular)
+            {
+                // Handle regular message
+            }
+
+            // New (struct)
+            if (messageType == StreamMessageType.Regular)
+            {
+                // Handle system message
+            }
+        }
+
+        internal void SwitchStatements()
+        {
+            // Old (enum)
+            // switch (messageType)
+            // {
+            //     case StreamMessageType.Regular:
+            //         // Handle regular message
+            //         break;
+            //     case StreamMessageType.System:
+            //         // Handle system message
+            //         break;
+            //     // ...
+            // }
+
+            StreamMessageType messageType = StreamMessageType.Regular;
+            
+            // New (struct) - Using if-else statements
+            if (messageType == StreamMessageType.Regular)
+            {
+                // Handle regular message
+            }
+            else if (messageType == StreamMessageType.System)
+            {
+                // Handle system message
+            }
+            
+            switch (messageType)
+            {
+                case var type when type == StreamMessageType.Regular:
+                    // Handle regular message
+                    break;
+                case var type when type == StreamMessageType.System:
+                    // Handle system message
+                    break;
+                // ...
+            }
+        }
+
+        internal void ExplicitInitialization()
+        {
+            StreamMessageType messageType = StreamMessageType.Regular;
+        }
+    
+        // Const-assignment alternative
+        public static readonly StreamMessageType DefaultMessageType = StreamMessageType.Regular;
+    }
+}