Add panic note to docstring

talpid-tunnel-config-client/src/classic_mceliece.rs

@@ -26,6 +26,10 @@ static KEYPAIR_RX: OnceLock<Mutex<mpsc::Receiver<KeyPair>>> = OnceLock::new();
 ///
 /// It can take upwards of 200 ms to generate McEliece key pairs so it needs to be done before we
 /// start connecting to the tunnel.
+///
+/// # Panic
+///
+/// Panics if the buffer capacity is 0.
 pub fn spawn_keypair_worker(bufsize: usize) -> mpsc::Receiver<KeyPair> {
     let (tx, rx) = mpsc::channel(bufsize);