public int rebalanceTimeoutMs() {
        int maxRebalanceTimeoutMs = 0;
        for (ClassicGroupMember member : members.values()) {
            maxRebalanceTimeoutMs = Math.max(maxRebalanceTimeoutMs, member.rebalanceTimeoutMs());
        }
        return maxRebalanceTimeoutMs;
    }
@return the group's rebalance timeout in milliseconds.
        It is the max of all members' rebalance timeout.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/classic/ClassicGroup.java