### Question:
CommandMetricsRegistry { public void add(String command, String sourceClientId, String targetClientId, String context, long duration) { try { timer(command, sourceClientId, targetClientId, context).record(duration, TimeUnit.MILLISECONDS); } catch (Exception ex) { logger.debug("Failed to create timer", ex); } } CommandMetricsRegistry(MeterFactory meterFactory); void add(String command,
                    String sourceClientId,
                    String targetClientId,
                    String context,
                    long duration); CommandMetric commandMetric(String command,
                                       String targetClientId,
                                       String context,
                                       String componentName); Gauge gauge(BaseMetricName name, T objectToWatch, ToDoubleFunction<T> gaugeFunction); MeterFactory.RateMeter rateMeter(String context, BaseMetricName meterName);  }### Answer:
@Test public void add() { ClientStreamIdentification client1 = new ClientStreamIdentification(Topology.DEFAULT_CONTEXT, "Client1"); }