private long updateEventStartMetricsAndGetTime(OptionalLong eventCreatedTimeNs) {
        long now = time.nanoseconds();
        controllerMetrics.incrementOperationsStarted();
        if (eventCreatedTimeNs.isPresent()) {
            controllerMetrics.updateEventQueueTime(NANOSECONDS.toMillis(now - eventCreatedTimeNs.getAsLong()));
        }
        return now;
    }
Checks that a configuration resource exists.
<p>
This object must be used only from the controller event thread.
metadata/src/main/java/org/apache/kafka/controller/QuorumController.java