wasi-tokio: WIP need to port the sync scheduler into a spawn_blocking

crates/wasi-common/tokio/src/sched.rs

@@ -0,0 +1,35 @@
+#[cfg(unix)]
+mod unix;
+#[cfg(unix)]
+use unix::poll_oneoff;
+
+#[cfg(windows)]
+mod windows;
+#[cfg(windows)]
+use windows::poll_oneoff;
+
+use wasi_common::{
+    sched::{Duration, Poll, WasiSched},
+    Error,
+};
+
+pub fn sched_ctx() -> Box<dyn wasi_common::WasiSched> {
+    struct AsyncSched;
+
+    #[wiggle::async_trait]
+    impl WasiSched for AsyncSched {
+        async fn poll_oneoff<'a>(&self, poll: &'_ Poll<'a>) -> Result<(), Error> {
+            poll_oneoff(poll).await
+        }
+        async fn sched_yield(&self) -> Result<(), Error> {
+            tokio::task::yield_now().await;
+            Ok(())
+        }
+        async fn sleep(&self, duration: Duration) -> Result<(), Error> {
+            tokio::time::sleep(duration).await;
+            Ok(())
+        }
+    }
+
+    Box::new(AsyncSched)
+}