private void metricRemoval(KafkaMetric metric) {
            log.debug("removing kafka metric : {}", metric.metricName());
            MetricKey metricKey = metricNamingStrategy.metricKey(metric.metricName());
            metricMap.remove(metricKey);
            doubleDeltas.remove(metricKey);
            metricAdded.remove(metricKey);
        }
Keeps track of the state of metrics, e.g. when they were added, what their getAndSet value is,
and clearing them out when they're removed.
clients/src/main/java/org/apache/kafka/common/telemetry/internals/KafkaMetricsCollector.java