I have something like this in my lorawan code
```rs
pub trait Timer: Sized {
    /// Notification of reaching a time point.
    type AtFuture<'a>: Future<Output = ()> + 'a
    where
        Self: 'a;
    /// Possible result error.
    type Error: Debug;

    /// Reset the timer.
    fn reset(&mut self);
    /// Set the timer to notify in the future.
    fn at<'a>(&self, millis: u64) -> Result<Self::AtFuture<'a>, Self::Error>;
}
```

I wrote(copied) it a good while ago and I am trying to figure out how to make it better. I want to be able to provide a timer implementation but I didn't want to lock it to something like embassy-time. This way of doing it requires type_alias_impl_trait and there should be some way to do this without that but I don't remember how