in src/common/metrics.js [87:96]
set(key, value) {
let parts = key.split('.');
let metricKey = key;
if (parts.length > 1) metricKey = parts[parts.length - 1];
if (!MetricKeys.includes(metricKey)) {
throw new Error(`Metric key "${metricKey}" is not supported.`);
}
this.setAny(key, value);
}