requestLiveStartOffset
open override fun requestLiveStartOffset(targetDurations: Double?, fallbackTargetDuration: Double?): Boolean
Makes THEOplayer itself begin a live source targetDurations × fallbackTargetDuration behind live, by re-setting the host's source with that liveOffset before its first frame loads. THEOplayer exposes no playlist target duration, so the fallback is required. Returns false once a frame loaded; a source that cannot be copied losslessly is left alone and the SDK seeks.