in ffwd-reporter/src/main/java/com/spotify/metrics/ffwd/FastForwardReporter.java [288:302]
private void reportHistogram(MetricId key, Histogram value) {
final Snapshot snapshot = value.getSnapshot();
if (snapshot.size() == 0) {
return;
}
key = MetricId.join(prefix, key);
final Metric m = FastForward
.metric(key.getKey())
.attributes(key.getTags())
.attribute(METRIC_TYPE, "histogram");
reportHistogram(m, snapshot);
}