@RawValue annotation is not applicable to target value parameter

I got the answer to this problem from Kotlang community.
Answer is you can not annotate the variable itself
but you have to annotate its type.

So annotating in the following way removes the error :

 var tokenType: @RawValue Any? = null

Though do not forget to write serilizer/deserializer for this property manually as it will not be done automatically.