Function timeout_checked 

pub fn timeout_checked<T, U>(dur: U, future: T) -> TimeoutChecked<T> 
where
    T: Future,
    U: Into<Millis>,

Requires a future to complete before dur has elapsed.

If the future completes before the duration has elapsed, then the completed value is returned. Otherwise, an error is returned and the future is canceled. A zero duration disables the timeout.