First. Thanks for your positive remarks concerning fapws.
Second. Very sorry for the limited documentation. The best approach is to look at the samples and the code. Contribution to.improve the documentation is very welcome.
Indeed "defer" is just to perform some tasks with a very low priority; typically when system becomes idle.
The third parameter is to combine the different defer and execute only one.
In other words, if 3rd parameter is true we will not enqueue an action already listed in the queue. We check the action AND his associated parameters.
William