Is it possible to spawn futures inside LocalExecutor without using a Rc?

[DontBreakAlex]

This does not build:

let runtime = smol::LocalExecutor::new();

smol::block_on(runtime.run(async {
   runtime
         .spawn(async {
            smol::Timer::after(std::time::Duration::from_secs(1)).await;
            info!("Timer expired");
            runtime
               .spawn(async {
                     smol::Timer::after(std::time::Duration::from_secs(1)).await;
                     info!("Timer expired");
               })
               .detach();
         })
         .detach();
}));

Because that would require having a ref like this: &'a LocalExecutor<'a>...
Using a Rc isn't very ergonomic either, because you need to have weak refs everywhere in futures so that the executor is dropped correctly when it goes out of scope.