code: private void instrument(String id, int port, MetricRegistry registry) {
          this.setPort(port);
          this.accepts = registry.meter(id + "-accepts");
          this.connects = registry.meter(id + "-connects");
          this.disconnects = registry.meter(id + "-disconnects");
          this.connections = registry.counter(id + "-active-connections");
  
      }
docs: Create metrics.
  
  @param id
  @param port
  @param registry