code: function pushLoadingState(xhrEvent, stateName, modelOrCollection, context, force) {
          var currentLoads = getState(stateName, context),
              currentlyLoading = currentLoads && currentLoads.length;
          if (!currentLoads) {
              currentLoads = [];
          }
          if (_.isArray(currentLoads)) {
              if (_.indexOf(currentLoads, xhrEvent) >= 0) {
                  if (!force) {
                      return;
                  }
                  
              } else {
                  currentLoads.push(xhrEvent);
              }
              
              if (!currentlyLoading) {
                  var toSet = {};
                  toSet[stateName] = currentLoads;
                  setState(toSet, context);
              }
  
              xhrEvent.on('complete', function() {
                  popLoadingState(xhrEvent, stateName, modelOrCollection, context);
              });
          }
      }
docs: loading state helpers