code: function createSlot() {
                      var handle = (nextHandle++).toString(),
                          slotNew = {
                              handle: handle,
                              item: null,
                              itemNew: null,
                              fetchListeners: null,
                              cursorCount: 0,
                              bindingMap: null
                          };
  
                      // Deliberately not initialized:
                      //   - directFetchListeners
  
                      handleMap[handle] = slotNew;
  
                      return slotNew;
                  }
docs: Slot List