code: private Invoker metered(Invoker invoker, List<Method> meteredMethods) {
  
          ImmutableMap.Builder<String, Meter> meters = new ImmutableMap.Builder<>();
  
          for (Method m : meteredMethods) {
              Metered annotation = m.getAnnotation(Metered.class);
              final String name = chooseName(annotation.name(), annotation.absolute(), m);
              Meter meter = metricRegistry.meter(name);
              meters.put(m.getName(), meter);
          }
  
          return new InstrumentedInvokers.MeteredInvoker(invoker, meters.build());
      }
docs: Factory method for MeteredInvoker.