I am not familiar with the SDK but you can watch for the returned response code (if you have access to it). If it is 401 (Unauthorized) then you can refresh the connection. This will probably require that you wrap each request in a try/catch block (I don't know if the SDK will throw an exception on 401).
Or you can just refresh the connection every 20 minutes - I currently use this approach but I am using the Rest API directly.