@Override
    public double combine(List<Sample> samples, MetricConfig config, long now) {
        double min = Double.MAX_VALUE;
        long count = 0;
        for (Sample sample : samples) {
            min = Math.min(min, sample.value);
            count += sample.eventCount;
        }
        return count == 0 ? Double.NaN : min;
    }
A {@link SampledStat} that gives the min over its samples.
clients/src/main/java/org/apache/kafka/common/metrics/stats/Min.java