chore: remove benches and fix/work around clippy lints (#1952)

examples/echo-udp.rs

@@ -51,7 +51,9 @@ impl Server {
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn Error>> {
-    let addr = env::args().nth(1).unwrap_or("127.0.0.1:8080".to_string());
+    let addr = env::args()
+        .nth(1)
+        .unwrap_or_else(|| "127.0.0.1:8080".to_string());
 
     let socket = UdpSocket::bind(&addr).await?;
     println!("Listening on: {}", socket.local_addr()?);