Function set_lockscreen_position_offset 

pub fn set_lockscreen_position_offset(
    _offset_seconds: f64,
) -> Result<(), String>

Set the base offset (seconds) added to positions reported to the Android lockscreen scrubber. Used by the background-audio handoff: the audio stream starts at the handoff point (StartTimeTicks), so ExoPlayer’s position is relative and must be shifted back to absolute to match the full duration. Pass 0.0 to clear on exit. No-op off Android.