SerializedMetrics ser = _cachedMetrics.get();
long now = _timeMaster.currentTimeMillis();
if (_shouldRefresh(forceRefresh, now, ser)) {
ExternalMetrics metrics = _gatherMetrics(now, full);
byte[] raw;
raw = _jsonWriter
// for diagnostics:
.withDefaultPrettyPrinter()
.writeValueAsBytes(metrics);