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

examples/echo.rs

@@ -33,7 +33,9 @@ async fn main() -> Result<(), Box<dyn Error>> {
     // Allow passing an address to listen on as the first argument of this
     // program, but otherwise we'll just set up our TCP listener on
     // 127.0.0.1:8080 for connections.
-    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());
 
     // Next up we create a TCP listener which will listen for incoming
     // connections. This TCP listener is bound to the address we determined