message: Avoid confusion by renaming `pk` to `private_key` in `small_network`
diff: @@ -473,11 +473,11 @@ where
  if let Some(endpoint) = self.endpoints.get(&node_id) {
  let ep = endpoint.clone();
  let cert = self.cert.clone();
  - let pk = self.private_key.clone();
  + let private_key = self.private_key.clone();
  effect_builder
  .set_timeout(Duration::from_millis(self.cfg.outgoing_retry_delay_millis))
  - .then(move |_| connect_outgoing(ep, cert, pk))
  + .then(move |_| connect_outgoing(ep, cert, private_key))
  .result(
  move |transport| Event::OutgoingEstablished { node_id, transport },
  move |error| Event::OutgoingFailed {
  