void notifyEpochChange(Optional<Integer> epoch, Optional<String> memberId) {
        stateUpdatesListeners.forEach(stateListener -> stateListener.onMemberEpochUpdated(epoch, memberId));
    }
Call all listeners that are registered to get notified when the member epoch is updated.
This also includes the latest member ID in the notification. If the member fails or leaves
the group, this will be invoked with empty epoch and member ID.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/MembershipManagerImpl.java