Function attach_tapped 

async fn attach_tapped(
    link: AnyLink,
    tap: Rc<RefCell<Option<PcapWriter>>>,
) -> Result<UlcpDevice<SessionLink>>

Attach to a link, wrapping it in the capture tap.

Administrative is the only relationship this tool has with a device: it administers radios rather than tethering to them, so the handle refuses host-domain writes.