public void start() {
    if (metricsCollectionMs > 0) {
      scheduledMetricsExecutor.scheduleAtFixedRate(() -> {
        collectMetrics();
      }, INITIAL_DELAY_MSEC, metricsCollectionMs, TimeUnit.MILLISECONDS);
    }
  }
Collect metrics from the llap daemons in every given milliseconds.
llap-tez/src/java/org/apache/hadoop/hive/llap/tezplugins/metrics/LlapMetricsCollector.java