docs: function() {
      if (_polling) {
        _closing = true;
        setTimeout(function() {
          if( _closing) {
            _.each(_brokers, function(broker) {
              broker.tearDown();
            });
          }
        }, _options.maxWait);
      }
      else {
        _.each(_brokers, function(broker) {
          broker.tearDown();
        });
      }
    }