private String formatMetricName(MetricRuleConfig rule, String meterRuleName) {
        StringJoiner metricName = new StringJoiner("_");
        metricName.add(rule.getMetricPrefix()).add(meterRuleName);
        return metricName.toString();
    }
toMeter transforms {@link SampleFamily} collection  to meter-system metrics.

@param sampleFamilies {@link SampleFamily} collection.
oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/MetricConvert.java