code: function ServerSession(request, socket, head, server) {
  	Session.call(this, request, socket, head);
  
  	this._resHeaders = {};
  	this._headerSent = false;
  
  	/**
  	 * The server instance of this session.
  	 * @type {Server}
  	 */
  	this.server = server;
  
  	/**
  	 * The HTTP status code of handshake.
  	 * @type    {Number}
  	 * @default 200
  	 */
  	this.statusCode = 200;
  
  	/**
  	 * The HTTP status message of handshake.
  	 * @type {String}
  	 */
  	this.statusMessage = '';
  }
docs: WebSocket Server Session
  @constructor
  @extends  Session
  @param    {IncomingMessage} request  see {@link Session#request}
  @param    {Socket}          socket   see {@link Session#socket}
  @param    {Buffer}          [head]   Data that received with headers.
  @param    {Server}          [server] see {@link ServerSession#server}