It's necessary to automatically re-acquire authn token in long-lived Kudu C++ client once current authn token expires. To get a new token, the client should use the primary user credentials.
NOTE: It's possible to get a new token only when primary user credentials are available. In case if a client is created using imported authenticaion_credentials (i.e. using KuduClientBuilder::import_authentication_credentials()), re-acquiring a new token is not possible by design.