[cnderrauber]

Depends on

• Add PrewarmedConnection to open the signalling connection ahead of connect rust-sdks#1667, plus a livekit-ffi release that includes it.

Before merging, bump the livekit-rtc/rust-sdks submodule and the FFI version, then regenerate the protos. The protos in this PR are already generated from the rust-sdks PR branch.

Summary

Exposes the Rust PrewarmedConnection in livekit-rtc: a TCP (+TLS) connection to the server opened ahead of Room.connect, so the connect only does the WebSocket upgrade.

• rtc.PrewarmedConnection.create(url): opens the connection; raises ConnectError on failure.
• .alive: whether it can still be used (not used or closed, and the server hasn't closed it).
• .close(): closes it without using it. Garbage collection also closes it.
• RoomOptions.prewarmed_connection: used by the first signal connect. If it's dead or for another host, connect dials fresh as usual.

Connect borrows the FFI handle, so Python keeps owning it and disposes it as normal.

conn = await rtc.PrewarmedConnection.create(url)
# ... later
await room.connect(url, token, rtc.RoomOptions(prewarmed_connection=conn))
conn.close()

Used by livekit/agents to keep a connection ready in idle job processes.

🤖 Generated with Claude Code