code: function Tracer(ringpop, config, opts) {
      if (!(this instanceof Tracer)) {
          return new Tracer(opts);
      }
  
      this.ringpop = ringpop;
      _.extend(this, config);
      this.opts = _.defaults({}, opts, tracerOptsDefaults);
      this.listener = null;
  }
docs: base for sink-specific tracers: A Tracer conjoins an internal node event and a user-defined sink, automatically forwarding data.