make wasi-cap-std-async work with wasmtime-wasi

Cargo.lock

@@ -3533,6 +3533,7 @@ name = "wasmtime-wasi"
 version = "0.26.0"
 dependencies = [
  "anyhow",
+ "wasi-cap-std-async",
  "wasi-cap-std-sync",
  "wasi-common",
  "wasmtime",

crates/wasi/Cargo.toml

@@ -15,6 +15,7 @@ build = "build.rs"
 [dependencies]
 wasi-common = { path = "../wasi-common", version = "0.26.0" }
 wasi-cap-std-sync = { path = "../wasi-common/cap-std-sync", version = "0.26.0", optional = true }
+wasi-cap-std-async = { path = "../wasi-common/cap-std-async", version = "0.26.0", optional = true }
 wiggle = { path = "../wiggle", default-features = false, version = "0.26.0" }
 wasmtime-wiggle = { path = "../wiggle/wasmtime", default-features = false, version = "0.26.0" }
 wasmtime = { path = "../wasmtime", default-features = false, version = "0.26.0" }
@@ -23,3 +24,4 @@ anyhow = "1.0"
 [features]
 default = ["sync"]
 sync = ["wasi-cap-std-sync"]
+async = ["wasi-cap-std-async", "wasmtime/async", "wasmtime-wiggle/async"]

crates/wasi/src/lib.rs

@@ -20,6 +20,13 @@ pub mod sync {
     pub use wasi_cap_std_sync::*;
 }
 
+/// Re-export the wasi-cap-std-async crate here. This saves consumers of this library from having
+/// to keep additional dependencies in sync.
+#[cfg(feature = "async")]
+pub mod async_ {
+    pub use wasi_cap_std_async::*;
+}
+
 /// An instantiated instance of all available wasi exports. Presently includes
 /// both the "preview1" snapshot and the "unstable" (preview0) snapshot.
 pub struct Wasi {
@@ -79,6 +86,7 @@ necessary. Additionally [`Wasi::get_export`] can be used to do name-based
 resolution.",
                 },
             },
+            async: { wasi_snapshot_preview1::{ poll_oneoff, sched_yield } }
         });
     }
     pub mod preview_0 {
@@ -106,6 +114,7 @@ necessary. Additionally [`Wasi::get_export`] can be used to do name-based
 resolution.",
                 },
             },
+            async: { wasi_unstable::{ poll_oneoff, sched_yield } }
         });
     }
 }