Show connection ID info when connection fails

This error path was coming up with some RecvError, which needs its own
investigation. For now, at least show which connection id failed.

Example log before this change:
ERROR utp_rs::socket: Failed to open connection with cid err=RecvError(())

Example after:
ERROR utp_rs::socket: Failed to open connection with ConnectionId { send: 8729, recv: 8728, peer: 127.0.0.1:3400 } err=RecvError(())

src/socket.rs

@@ -342,6 +342,7 @@ where
 
         self.pause_while_stressed().await;
 
+        let cid_info = format!("{:?}", cid);
         let stream = UtpStream::new(
             cid,
             config,
@@ -360,7 +361,7 @@ where
                 Err(err)
             }
             Err(err) => {
-                tracing::error!(?err, "Failed to open connection with cid");
+                tracing::error!(?err, "Failed to open connection with {cid_info}");
                 Err(io::Error::from(io::ErrorKind::TimedOut))
             },
         }