@Override
    public String toString() {
        return "Meter(" +
            "rate=" + rate +
            ", total=" + total +
            ", rateMetricName=" + rateMetricName +
            ", totalMetricName=" + totalMetricName +
            ')';
    }
Construct a Meter with provided time unit
clients/src/main/java/org/apache/kafka/common/metrics/stats/Meter.java