Function wait_for_first

pub fn wait_for_first<FutOne, FutTwo, T, R>(
    one: FutOne,
    two: FutTwo,
) -> WaitForFirst<FutOne, FutTwo>
where
    FutOne: Future<Output = T>,
    FutTwo: Future<Output = R>,

A future that waits on two sub-futures until the first one completes. If the second one completes first, this future will continue awaiting on the first future. If the first one completes first, this future returns immediately without continuing to wait on the second future.