code: function(id, msg) {
  
          var q = queues[id], sc;
          if (q.timer) {
              // q.timer.cancel();
              clearTimeout(q.timer);
          }
  
          // execute failure callback
          if (q.onFailure) {
              sc = q.context || q;
              q.onFailure.call(sc, _returnData(q, msg));
          }
  
          _end(id, msg, 'failure');
      }
docs: hash of queues to manage multiple requests
  @property queues
  @private