Function fan_out 

fn fan_out(
    ring: &Ring,
    server: &Server,
    v4l2out: &mut Option<V4l2Output>,
    device_path: &Mutex<String>,
    pipewire: &mut Option<PipeWireSink>,
    ts: u64,
    stats: &Stats,
)

After a publish: wake the socket clients and mirror the frame into the kernel device and the PipeWire node where those sinks are up, retiring a sink that failed.