boolean putMetrics(MetricsBuffer buffer, long logicalTime) {
        if (logicalTime % period == 0) {
            LOG.debug("enqueue, logicalTime=" + logicalTime);
            if (queue.enqueue(buffer)) {
                qsize.set(queue.size());
                return true;
            }
            dropped.incr();
            return false;
        }
        return true; // OK
    }