private static AthenzRole toRole(StringBuilder rawRole, AthenzResourceName resourceName) {
        if (rawRole.length() == 0) {
            return null;
        } else {
            return new AthenzRole(resourceName.getDomain(), rawRole.toString());
        }
    }
The default implementation of {@link Zpe}.
This implementation is currently based on the official Athenz ZPE library.

@author bjorncs
vespa-athenz/src/main/java/com/yahoo/vespa/athenz/zpe/DefaultZpe.java