public boolean allMembersUseClassicProtocolExcept(String memberId) {
        return numClassicProtocolMembers() == members().size() - 1 &&
            !getOrMaybeCreateMember(memberId, false).useClassicProtocol();
    }
Checks whether all the members use the classic protocol except the given member.

@param memberId The member to remove.
@return A boolean indicating whether all the members use the classic protocol.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/modern/consumer/ConsumerGroup.java