Futures 0.3.0, change future::select to future::select!

The code below is valid for 'futures' 0.1

let future = ... // some future
let timeout = ... // future with timeout
let app = future.select(tiemout); // it was available in 'futures' 0.1

ThreadPool::new()
       .expect("Failed to create threadpool")
        .run(app)
        .unwrap();

How it can be refactored for using with 'futures-preview' 0.3 ?