ExoPlayer is unable to detect the presence of subtitle tracks in some
MPEG-TS files that don't fully declare them. It's possible for a
developer to provide the list instead, but doing so is quite awkward
without this helper method. This is consistent for how
`DefaultExtractorsFactory` allows other aspects of the delegate
`Extractor` implementations to be customised.
* Issue: google/ExoPlayer#10175
* Issue: google/ExoPlayer#10505
#minor-release
PiperOrigin-RevId: 490214619
(cherry picked from commit 4853444f0dc90163c257d0e20962604510557df4)
Also consolidate the threading warning info with the same info on the
hello world page and update the version that the
setThrowsWhenUsingWrongThread() method will be removed in.
PiperOrigin-RevId: 369657759
