future::loop_fn(timer, |timer| {
        match timer.wait() {
            Ok(())                     => Ok(Loop::Break(timer)),
            Err(nb::Error::WouldBlock) => Ok(Loop::Continue(timer)),
        }
    })

pub trait Timer {
    type Time;
    fn get_timeout(&self) -> Self::Time;
    fn pause(&mut self);
    fn restart(&mut self);
    fn resume(&mut self);
    fn set_timeout<T>(&mut self, timeout: T)
    where
        T: Into<Self::Time>;
    fn wait(&self) -> Result<(), !>;
}