private static String partitionRecordsLeadMetricName(TopicPartition tp) {
        return tp + ".records-lead";
    }
This method is called by the {@link Fetch fetch} logic before it requests fetches in order to update the
internal set of metrics that are tracked.

@param subscription {@link SubscriptionState} that contains the set of assigned partitions
@see SubscriptionState#assignmentId()
clients/src/main/java/org/apache/kafka/clients/consumer/internals/FetchMetricsManager.java