message: Add error message when invalid interface is provided
diff: @@ -234,7 +234,7 @@ fn main() {
  .into_iter()
  .filter(interface_names_match)
  .next()
  - .unwrap();
  + .unwrap_or_else(|| panic!("No such network interface: {}", iface_name));
  // Create a channel to receive on
  let (_, mut rx) = match datalink::channel(&interface, Default::default()) {
  