Interaction between eio and domainslib, unhandled exceptions?

Ecosystem
,
1

Hello,
I am trying to build something using both eio and domainslib, and I’m quite stumped by their interaction.
According to the readme of eio, calls to various functions require a Eio.Stdenv.t, most likely given by Eio_main.run.
On the other hand, according to its documentation domainslib states that “[The run] function should be used at the top level to enclose the calls to other functions that may await on promises. This includes await, parallel_for and its variants. Otherwise, those functions will raise Unhandled exception.”
Armed with this, I wrote this MWE:

module T = Domainslib.Task

let task pool sink =
  T.parallel_for ~start:0 ~finish:1024
    ~body:(fun i -> if i mod 2 = 0 then Eio.Flow.copy_string "Hello!\n" sink)
    pool

let () =
  let pool =
    T.setup_pool ~num_domains:(Domain.recommended_domain_count () - 1) ()
  in
  T.run pool (fun () ->
      Eio_main.run (fun env ->
          let stdout = Eio.Stdenv.stdout env in
          task pool stdout));
  T.teardown_pool pool

Running this with eio = 0.9, domainslib = 0.5, ocaml = 5.0.0, on a machine where Domain.recommended_domain_count is 8 gets the following result:

Hello!
Hello!
Hello!
Hello!
Hello!
Hello!
Hello!
Hello!
Fatal error: exception Stdlib.Effect.Unhandled(Eio_linux__Sched.Alloc)

So, only 8 Hellos instead of the expected 512, and a nice crash to boot.
At first I thought I had messed up my calls to run functions, and tried swapping Eio_main.run and T.run around to check.
Same error.
On more involved examples, I also got the following error:

Fatal error: exception Multiple exceptions:
- Invalid_argument("Cancellation context accessed from wrong domain!")
- Invalid_argument("exit: 1 request(s) still active!")

I don’t really understand how to proceed from here. Are Eio and Domainslib just not supposed to work together? Is there something obvious I missed?

Thanks all