void rebalanceSucceeded(long now) {
            long duration = Math.max(0L, now - rebalanceStartedAtMillis);
            rebalancing = false;
            rebalanceCompletedCounts.record(1.0);
            rebalanceTime.record(duration);
            lastRebalanceCompletedAtMillis = now;
        }
A collection of cluster rebalance related metrics.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/DistributedHerder.java