@Override
    public void registerChecker(Checker checker) {
        checkerScheduler.scheduleWithFixedDelay(() -> {
            loadLevels.put(checker.source(), checker.check());
            maybeRegulate();
        }, 0, checker.intervalMs(), TimeUnit.MILLISECONDS);
    }
The current state metrics of the system.
Only used for monitoring.

@see S3StreamKafkaMetricsManager#setBackPressureStateSupplier
core/src/main/java/kafka/automq/backpressure/DefaultBackPressureManager.java