Function shutdown_signal 

pub async fn shutdown_signal(handle: ServerHandle)

Signal to graceful shutdown.

Required to be manually awaited, if you start server with start_clean/start_with_service functions. Example:

let (server, handle) = start_clean(app_state, app_config, router).await.unwrap();
let default_handle = tokio::spawn(async move { shutdown_signal(handle).await });

tracing::info!("Server is booted.");

tokio::select! {
  _ = server         => tracing::info!("Server is shutdowned."),
  _ = default_handle => std::process::exit(0),
}

Graceful coroutine starts automatically with start function.