Function teardown_capture 

pub(crate) fn teardown_capture(
    cap: &mut WlCapture,
) -> (Option<JoinHandle<()>>, Option<JoinHandle<Option<FrameEncoder>>>)

Tear down a capture’s encode/delivery threads and pools, returning both join handles as (deliver, encode) for the caller to place. NEITHER is joined here: this runs on the calloop thread, which also dispatches Wayland clients and input, and either thread can be parked behind a consumer still inside Python. A restart hands each handle to its successor thread, which joins it off the event loop — the encode successor inheriting the readback hardware session, the deliver successor keeping stripes in capture order across the restart — and a plain stop hands both to the reaper. The zero-copy session (if any) is left on the capture for the caller to reuse or drop, and so are the host frames its thread may still be reading (release_host_inflight).