Question: Is it possible to pause and resume buffering of AVPlayer?

Answer: 
according to my test,`preferredForwardBufferDuration` should be greater or equal to 1.0,if it is below 1.0,default buffer duration will be used.
AV player buffers the video in several cases, however no clear documentation on them. You can check currentItem.loadedTimeRanges to see what's going on more info can be found on this thread [AVPlayer buffering, pausing notification, and poster frame](https://stackoverflow.com/questions/10648963/avplayer-buffering-pausing-notification-and-poster-frame)