public Optional<Long> lastDeployedSession() {
        return Optional.of(lastDeployedSession)
                .filter(OptionalLong::isPresent)
                .map(OptionalLong::getAsLong);
    }
Data class for application id, active session and last deployed session

@author hmusum
configserver/src/main/java/com/yahoo/vespa/config/server/application/ApplicationData.java