Issues with async support / Tokio

I attempt to compile the following code with experimental-async feature enabled:

#[pyclass]
struct Sender {
    _inner: IPCSender
}

#[pymethods]
impl Sender {
    #[new]
    async fn new(printname: String) -> PyResult<Self> {
        let ipcsender = IPCSender::new(&printname).await?;

        Ok(Self { _inner: ipcsender })
    }
}

#[pymodule]
fn python_ipc(m: &Bound<'_, PyModule>) -> PyResult<()> {
    m.add_function(wrap_pyfunction!(sum_as_string, m)?)?;
    m.add_class::<Sender>()?;
    Ok(())
}

However, I get this error message:

error[E0599]: no method named `convert` found for opaque type `impl Future<Output = Result<Sender, PyErr>>` in the current scope
  --> src/lib.rs:11:1
   |
11 | #[pymethods]
   | ^^^^^^^^^^^^ method not found in `impl Future<Output = Result<Sender, PyErr>>`
   |
   = note: this error originates in the attribute macro `pymethods` (in Nightly builds, run with -Z macro-backtrace for more info)

I tried adding:

    static RT: OnceLock<tokio::runtime::Runtime> = OnceLock::new();
    RT.get_or_init(|| tokio::runtime::Runtime::new().expect("Unable to start Tokio runtime"));

to python_ipc function, but it still doesn't work.
IPCSender is a struct from a local crate, which uses tokio runtime.

Reproduce the report from src/lib.rs with the experimental-async feature and the async #[new] method shown. Start by inspecting how the #[pymethods] macro handles async constructors and compare that with async methods. Done means establishing whether this constructor pattern is supported and resolving or documenting the limitation.