public long numClassicGroups(ClassicGroupState state) {
        AtomicLong counter = classicGroupGauges.get(state);
        if (counter != null) {
            return counter.get();
        }
        return 0L;
    }
Obtain the number of classic groups in the specified state.

@param state  The classic group state.

@return   The number of classic groups in `state`.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/metrics/GroupCoordinatorMetricsShard.java