Working with a non static executor?

[TuTiuTe]

Hello, I am trying to use the crate smol-axum, but I've encountered a compile error (documented better here notgull/smol-axum#3)

TL;DR + additional info: this change 58e0e7d seems to be breaking smol-hyper's implementation of Executor, which implements it over async_executor's executors. It goes like this:

impl<'a, E: AsRef<async_executor::Executor<'a>> + ?Sized, Fut: Future + Send + 'a> hyper::rt::Executor<Fut>
    for SmolExecutor<E>
where
    Fut::Output: Send + 'a,
{
    #[inline]
    fn execute(&self, fut: Fut) {
        self.get_ref().as_ref().spawn(fut).detach();
    }
}

Where SmolExecutor is a wrapper to a type that derefs to an executor from smol crate

The issue lies when passing this smol executor to an http2 builder and calling serve (try to compile smol-axum's hello example after running cargo update), the reference in SmolExecutor goes out of scope but the SmolExecutor is still in use

As the author of both crates has stated that they won't be very active now, I wanted to help out and fix this myself, however I lack the technical skill, and trying to get to understand this project is a hard task.

I struggle to find what's so different after the commit that made this no longer work, I'd guess the fact there is an added E generic trait parameter to a lot of types is holding hostage the SmolExecutor but not the underlying executor which slips out of scope

Reading what I can find about hyper's executor trait, all the examples operate over a globally defined executor, with static lifetimes, so there's never an issue

So, my question is: Is the implementation of an Executor over a non static lifetime possible, or was it an oversight to begin with?
If it's possible, an example would be much appreciated. If it's not, what could be done to circumvent the issue, aside from the worst case scenario of "make the executor global" which defeats the whole purpose of using smol imo