public Optional<Integer> classicProtocolSessionTimeout() {
        if (useClassicProtocol()) {
            return Optional.ofNullable(classicMemberMetadata.sessionTimeoutMs());
        } else {
            return Optional.empty();
        }
    }
@return The session timeout if the member uses the classic protocol.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/modern/consumer/ConsumerGroupMember.java