private void setAttrCacheTag(MetricsTag tag, int recNo) {
String key = tagName(tag.name(), recNo);
attrCache.put(key, new Attribute(key, tag.value()));
}
@Override
public MetricsRecordBuilder add(MetricsTag metricsTag) {
tags.put(canonicalizeMetricName(metricsTag.name()), metricsTag.value());
return this;
}