Rust SDKs

The SDKs expanded their data transport capabilities while tightening media handling. Data tracks shipped across livekit and livekit-ffi, enabling arbitrary data streaming alongside audio and video. In parallel, video buffering moved from unbounded queues to configurable bounded buffers defaulting to single-frame depth, eliminating lag during slow rendering or background wake-ups and keeping video synchronized with audio. The webrtc-sys layer upgraded to libwebrtc m144.