docs: function callbacks(err) {
        var fn = route.callbacks[i++];
        try {
          if ('route' == err) {
            nextRoute();
          } else if (err && fn) {
            if (fn.length < 4) return callbacks(err);
            fn(err, req, res, callbacks);
          } else if (fn) {
            if (fn.length < 4) return fn(req, res, callbacks);
            callbacks();
          } else {
            nextRoute(err);
          }
        } catch (err) {
          callbacks(err);
        }
      }