docs: public Timer timer(String name, final MetricSupplier<Timer> supplier) {
          return getOrAdd(name, new MetricBuilder<Timer>() {
              @Override
              public Timer newMetric() {
                  return supplier.newMetric();
              }
  
              @Override
              public boolean isInstance(Metric metric) {
                  return Timer.class.isInstance(metric);
              }
          });
      }