Getting the amount of audio loaded in an AVPlayer

I have AVPlayer loading an MP3 from a URL. While it is playing, how can I tell how much of the MP3 has been actually downloaded so far? I have tried using item.loadedTimeRanges, but it does not seem to be accurate. I get a few notifications but it usualy stops sending notifications around 80 seconds and doesn't keep up to even the current position of the player.

Any idea?

Also, is there any way to get the total duration of the audio? All the methods I've tried return NAN.

Getting the amount of audio loaded in an AVPlayer
 
 
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