fix: Incorrect stop reason

[iamszabo]

At some cases an STKAudioPlayerStopReasonNone declared although the file reached the end. The issue can be reproduced from time to time when seeked to the end of the file.

It happens as one thread declares that the file is ended on OutputRenderCallback and another thread declares the ending reason on the processRunloop. If the file ended thread happens first the stop reason won't be set. My fix makes sure when the lastFrame is played the end reason will be set as STKAudioPlayerStopReasonEof

[ruduss]

Would it be best for us to do the additional check of STKAudioPlayerStopReasonNone in our code rather than make the change in STKAudioPlayer?
eg in FileAudioService the change could be:

@objc func audioPlayer(_ audioPlayer: STKAudioPlayer!, didFinishPlayingQueueItemId queueItemId: NSObject!,
                          with stopReason: STKAudioPlayerStopReason, andProgress progress: Double, andDuration duration: Double) {
       if stopReason == STKAudioPlayerStopReasonEof || stopReason == STKAudioPlayerStopReasonNone  {
           self.audioCompletedSubject.onNext(())
       }
   }

[iamszabo]

@ruduss I considered this option, the issue with STKAudioPlayerStopReasonNone is that, we don't know what is the reason why the audio has stopped. That is the default value when no other reason has specified. For example, it will return STKAudioPlayerStopReasonNone when you change the audio source by playing something else.

STKAudioPlayerStopReasonEof is retuned when we reached the end of the file itself, and it's a signal for us to play the next episode on the list.