Method vmctx_async

crates/wasmtime/src/runtime/func.rs:2310–2343

(
        engine: &Engine,
        ty: FuncType,
        ctx: U,
        func: F,
    )

    /// captured in the closures generated here.
    #[cfg(feature = "async")]
    fn vmctx_async<F, T, U>(
        engine: &Engine,
        ty: FuncType,
        ctx: U,
        func: F,
    ) -> Result<StoreBox<VMArrayCallHostFuncContext>, OutOfMemory>
    where
        F: for<'a> Fn(
                Caller<'a, T>,
                &'a mut [MaybeUninit<ValRaw>],
                &'a U,
            ) -> Box<dyn Future<Output = Result<()>> + Send + 'a>
            + Send
            + Sync
            + 'static,
        T: 'static,
        U: Send + Sync + 'static,
    {
        // Eventually we want to remove `with_blocking` + `block_on` from
        // Wasmtime. For now this is the attempt to keep it as low-level as
        // possible.
        //
        // Generally it's a lie to run async things on top of sync things and
        // it's caused many headaches. For now it's the best that can be done.
        Self::vmctx_sync(engine, ty, move |Caller { store, caller }, args| {
            store.with_blocking(|store, cx| {
                cx.block_on(core::pin::Pin::from(func(
                    Caller { store, caller },
                    args,
                    &ctx,
                )))
            })?
        })
    }

    /// Entrypoint of WebAssembly back into the host.
    ///