feature: add the possibility to rely on managedMediaSource on iOS devices

[Florent-Bouisset]

Add the possibility to rely on ManagedMediaSource for devices that has no access to MediaSource such as iOS devices with version > 17.1

In practice that allow devices like iPhone to play DASH content with the RxPlayer.

Note that it is not possible to cast a DASH content with AirPlay, so the RxPlayer disable the possibility to stream to AirPlay by adding the disableRemotePlayback attribute to the video Element when a DASH content is loaded.

#1294

[peaBerberian]

Aren't there also supplementary events we're supposed to handle as a player with a ManagedMediaSource?
To me that was one of the arguments for it.

I know there's the potentiality of GC at any time, which I think we prefer and already support, and that brings the bufferedchange event which we could use but nothing urgent for that one.
But there's also mainly the stopStreaming / startStreaming events on which we're supposed to pause / resume our [adequately named] stream logic (the loading and pushing segments operations), no?

[peaBerberian]

So if I get it, we will not be reacting to startstreaming/endstreaming directly but we'll just check mediaSource.streaming in the next playback observation.

I wonder if it's what we want:

• For endstreaming, it depends on the philosophy of the event. I'm not sure of what is wanted from us here by reading the spec.
• For startstreaming, it depends on what the user-agent defined as its [cannot] play uninterrupted and efficiently limit...

[peaBerberian]

We could also have a supplementary parameter streamingReference everywhere but I understand that it is less nice than having it in a playback observation

[Florent-Bouisset]

So if I get it, we will not be reacting to startstreaming/endstreaming directly but we'll just check mediaSource.streaming in the next playback observation.

I wonder if it's what we want:

• For endstreaming, it depends on the philosophy of the event. I'm not sure of what is wanted from us here by reading the spec.
• For startstreaming, it depends on what the user-agent defined as its [cannot] play uninterrupted and efficiently limit...

Don't know if the comment is outdated, but it actually send an event streamingChanged and the playbackObserver emit a new observation on the "endstreaming" and "startstreaming" event.
The value is passed down to the representationStream and to the segmentQueue. The next time a segment is intended to be loaded the segmentQueue it check the value on the last observation, so It should be OK.