Add a use of route_service with ServeFile to the static-file-server example (#2361)

examples/static-file-server/src/main.rs

@@ -32,6 +32,7 @@ async fn main() {
         serve(using_serve_dir_with_handler_as_service(), 3004),
         serve(two_serve_dirs(), 3005),
         serve(calling_serve_dir_from_a_handler(), 3006),
+        serve(using_serve_file_from_a_route(), 3307),
     );
 }
 
@@ -101,6 +102,10 @@ fn calling_serve_dir_from_a_handler() -> Router {
     )
 }
 
+fn using_serve_file_from_a_route() -> Router {
+    Router::new().route_service("/foo", ServeFile::new("assets/index.html"))
+}
+
 async fn serve(app: Router, port: u16) {
     let addr = SocketAddr::from(([127, 0, 0, 1], port));
     let listener = tokio::net::TcpListener::bind(addr).await.unwrap();