private void updateClientSubscription(String subscriptionName, ClientMetricsConfigs configs) {
        List<String> metrics = configs.getList(ClientMetricsConfigs.SUBSCRIPTION_METRICS);
        int pushInterval = configs.getInt(ClientMetricsConfigs.PUSH_INTERVAL_MS);
        List<String> clientMatchPattern = configs.getList(ClientMetricsConfigs.CLIENT_MATCH_PATTERN);

        SubscriptionInfo newSubscription =
            new SubscriptionInfo(subscriptionName, metrics, pushInterval,
                ClientMetricsConfigs.parseMatchingPatterns(clientMatchPattern));

        subscriptionMap.put(subscriptionName, newSubscription);
    }
Handles client telemetry metrics requests/responses, subscriptions and instance information.
server/src/main/java/org/apache/kafka/server/ClientMetricsManager.java