with msgpack-cli

fuckingil2cpp.cs

                SerializationContext context = new SerializationContext()
                {
                    SerializationMethod = SerializationMethod.Array,
                    EnumSerializationMethod = EnumSerializationMethod.ByUnderlyingValue
                };

                var intSerializer = context.GetSerializer<int>();
                var result = intSerializer.PackSingleObject(100);
                var resultV = intSerializer.UnpackSingleObject(result);
                
                Debug.Log(resultV);