function next(err){
    if (++i >= self._index.length) {
      if (err) return self.onStatError(err);
      return self.error(404);
    }

    var p = join(path, self._index[i]);

    debug('stat "%s"', p);
    fs.stat(p, function(err, stat){
      if (err) return next(err);
      if (stat.isDirectory()) return next();
      self.emit('file', p, stat);
      self.send(p, stat);
    });
  }
Transfer index for `path`.

@param {String} path
@api private