Crash after unwrap fails

[iopq]

Describe the bug
When I run it, I get a stack trace

it points to this code

    let tun = TunBuilder::new()
        .name(tun_name) // if name is empty, then it is set by kernel.
        .up() // or set it up manually using `sudo ip link set <tun-name> up`.
        .address(tun_local)
        .destination(tun_peer)
        .queues(num_cpus)
        .build()
        .unwrap();

line 161 in client

Operating system

NixOS (Linux)

tcpdump between the server and client on Phantun's port

can't run the program, would be helpful not to unwrap, but to show what failed so instead of a stack trace I get a helpful error message

[iopq]

This was because of lacking permissions, so the code shouldn't use unwrap, but check for Error when creating tunnel and explain why it wasn't able to create a tunnel