Fix user option values on .NET 5+

Core/Data/BotUserValue.cs

@@ -1,7 +1,10 @@
 using System;
 using System.ComponentModel.DataAnnotations;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Runtime.Serialization.Formatters.Binary;
+using System.Text.Json;
+using System.Xml.Serialization;
 
 namespace Kruzya.TelegramBot.Core.Data
 {
@@ -13,30 +16,27 @@ namespace Kruzya.TelegramBot.Core.Data
         public BotUser BotUser { get; set; }
         public string Name { get; set; }
         
-        public byte[] Value
-        {
-            get
-            {
-                var fmt = new BinaryFormatter();
-                using var memStream = new MemoryStream();
-                fmt.Serialize(memStream, data);
-                
-                return memStream.ToArray();
-            }
-            set
-            {
-                var fmt = new BinaryFormatter();
-                using var memStream = new MemoryStream();
-                memStream.Write(value);
-                memStream.Position = 0;
+        public string ValueType { get; set; }
 
-                data = fmt.Deserialize(memStream);
+        public byte[] Value { get; set; }
+
+        public T GetValue<T>(T defVal = default)
+        {
+            try
+            {
+                return JsonSerializer.Deserialize<T>(new ReadOnlySpan<byte>(Value));
+            }
+            catch (Exception)
+            {
+                return defVal;
             }
         }
 
-        [NonSerialized] public object data;
-        
-        public T GetValue<T>() => (T) data;
-        public void SetValue<T>(T value) => data = value;
+        public void SetValue<T>(T value)
+        {
+            Value = JsonSerializer.SerializeToUtf8Bytes(value, new JsonSerializerOptions { WriteIndented = false, 
+                IgnoreNullValues = true });
+            ValueType = value.GetType().FullName;
+        }
     }
 }