code: function ZD(conf) {
    if (!(this instanceof ZD)) return new ZD(conf);
    var config = ('string' === typeof conf) ? { conn: conf } : (conf || {});
    this.dubbo = config.dubbo;
    this.client = zookeeper.createClient(config.conn, {
      sessionTimeout: config.sessionTimeout,
      spinDelay: config.spinDelay,
      retries: config.retries
    });
  }
docs: Constructor of ZD.
  
  @param {String|Object} conf // A String of host:port pairs or an object to set options.
  {
  dubbo: String // Dubbo version information.
  
  // The following content could reference:
  //     https://github.com/alexguan/node-zookeeper-client#client-createclientconnectionstring-options
  
  conn: String, // Comma separated host:port pairs, each represents a ZooKeeper server
  sessionTimeout: Number, // Session timeout in milliseconds, defaults to 30 seconds.
  spinDelay: Number, // The delay (in milliseconds) between each connection attempts.
  retries: Number // The number of retry attempts for connection loss exception.
  }
  @returns {ZD}
  @constructor