Axum Example not working

[DatabaseConnection] is passed as State .with_state(state) in Axum Server but this don't work. [DatabaseConnection] can't be shared across threads.

In examples/axum_example/api/src/lib.rs

...
#[derive(Clone)]
struct AppState {
    templates: Tera,
    conn: DatabaseConnection,
}
...
dotenvy::dotenv().ok();
let db_url = env::var("DATABASE_URL").expect("DATABASE_URL is not set in .env file");
let conn = Database::connect(db_url)
        .await
        .expect("Database connection failed");
let templates = ...
let state = AppState { templates, conn };
...
let app = Router::new()
        .route("/", get(list_posts).post(create_post))
        ...
        .with_state(state);
...

Start in examples/axum_example/api/src/lib.rs and inspect how AppState, DatabaseConnection, and .with_state(state) are assembled. Run the Axum example to reproduce the thread-sharing error, then verify that the example builds and starts successfully with the database connection in its state.