function SendStream(req, path, options) {
  var self = this;
  this.req = req;
  this.path = path;
  this.options = options || {};
  this.maxage(0);
  this.hidden(false);
  this.index('index.html');
}
Initialize a `SendStream` with the given `path`.

Events:

 - `error` an error occurred
 - `stream` file streaming has started
 - `end` streaming has completed
 - `directory` a directory was requested

@param {Request} req
@param {String} path
@param {Object} options
@api private