public Collection<String> getAllMetricNames() {
        Set<String> names = new HashSet<>();
        for (Identifier id : values.keySet()) {
            names.add(id.getName());
        }
        return names;
    }
An aggregation of data which is only written to from a single thread.

@author Steinar Knutsen
container-core/src/main/java/com/yahoo/metrics/simple/Bucket.java