Change suggested by cargo build.

src/main.rs

@@ -4,7 +4,7 @@ use std::net::UdpSocket;
 
 fn main() -> std::io::Result<()> {
     let socket_result: Result<UdpSocket, std::io::Error> = UdpSocket::bind("127.0.0.1:7878");
-    let mut socket: UdpSocket = match socket_result {
+    let socket: UdpSocket = match socket_result {
         Ok(s) => s,
         Err(e) => {
             println!("Failed to bind socket: {}", e);
@@ -28,7 +28,6 @@ fn main() -> std::io::Result<()> {
             String::from_utf8_lossy(&buffer[..bytes_received])
         );
 
-
         // Echo the data back to the client
         socket.send_to(&buffer[..bytes_received], src_addr)?;
     }