Apply Copilot suggestion

Author: SajjadPourali

examples/tun.rs

@@ -92,12 +92,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     });
 
     let mut ipstack_config = ipstack::IpStackConfig::default();
-    let mut tcp_config = ipstack::TcpConfig::default();
-    tcp_config.options = Some(vec![ipstack::TcpOptions::MaximumSegmentSize(1460)]);
-    ipstack_config.with_tcp_config(tcp_config);
     ipstack_config.mtu(MTU);
     let mut tcp_config = ipstack::TcpConfig::default();
     tcp_config.timeout = std::time::Duration::from_secs(args.tcp_timeout);
+    tcp_config.options = Some(vec![ipstack::TcpOptions::MaximumSegmentSize(1460)]);
     ipstack_config.with_tcp_config(tcp_config);
     ipstack_config.udp_timeout(std::time::Duration::from_secs(args.udp_timeout));