These tasks are just like regular load and unload tasks except that right before the TaskExecuter moves the flowitem, it notifies the FixedResource of the operation being done, so that the FixedResource can appropriately decrement its nroftransportsin/nroftransportsout variable. In summary, the nroftransportsout of the upstream object and the nroftransportsin variable of the downstream object are both incremented at the same time that the Request Transport From function is called and the task sequence is created. The nroftransportsout variable is then decremented just before the TaskExecuter finishes the frload tasks and moves the flowitem out of the upstream object. The nroftransportsin variable is decremented just before the TaskExecuter finishes an frunload task and moves the flowitem into the downstream object.
上述原文表明：Load 与Frload 基本相似，只是使用Frload可以使得任务执行器在移到临时实体前会通报上游固定资源实体和下游固定资源实体它将要执行装载任务，这时上游固定资源实体要将其nroftransportsout的值增加，同时下游固定资源实体也会将其 nroftransportsin 增加。装载完毕开始移向下游实体时上游的nroftransportsout马上减少。卸载临时实体并将其移到下游固定实体前下游固定实体的 nroftransportsin 减小。而这些功能是load所不具备的。
