Function print_tunnel_closed_json 

pub fn print_tunnel_closed_json(event: &TunnelClosedJson) -> Result<()>

Emits the tunnel_closed shutdown event (G-TUN-R07).

Always emitted, including on the happy deadline path, so an agent can tell the three endings apart instead of inferring them from a shared exit 0.

Errors

Serialization or stdout I/O (including BrokenPipe).