Problem:
- tokio::join!() waited for both cache_future AND pump_future to complete
- cache_future returned after prebuffer (~530ms)
- pump_future read entire first track (~19s)
- Track only pushed to playlist after both finished → 19s delay
Solution (Solution A from OPTIMIZATION_PREBUFFER_TO_PLAYLIST.md):
- Created pump_track_segments_owned() that takes ownership of rx and returns it
- Spawned pump in tokio::spawn to run independently
- Wait for cache_future alone → push to playlist immediately
- Wait for pump_handle later to recover rx for next track
Results (tested with play_and_cache --null-audio):
Before:
- Prebuffer → playlist: ~19s
- Prebuffer → playback: ~19.5s
After:
- Prebuffer → playlist: ~24ms
- Prebuffer → playback: ~76ms
- Improvement: 99.6% (250x faster!)
Target was <1s, achieved 76ms (13x better than target!)
Changes:
- Added pump_track_segments_owned() in flac_cache_sink.rs:516
- Modified FlacCacheSinkLogic::process() to use tokio::spawn pattern
- Added timing logs (INFO level) for prebuffer and playlist push
- rx ownership properly managed: moved to pump, returned, recovered
Tests passed:
✅ Prebuffer completes in ~530ms (512KB downloaded)
✅ Track pushed to playlist in ~24ms after prebuffer
✅ Playback starts in ~76ms after prebuffer
✅ rx properly recovered for next tracks
✅ No panics or deadlocks
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