code: function next(err) {
        return finish(function (finishErr) {
          if (err) return topnext(err);
          else if (finishErr) return topnext(finishErr);
          else return topnext();
        });
      }
docs: Override the next() error/passthrough handler to clean up before leaving. This way, the timer doesn't go off / the subscriber doesn't handle messages after we've sent the response, and the server doesn't crash as a result.