Minimal optimization for cap-async-std.

Use `spawn_blocking` to run important blocking tests off the main
thread.

Author: sunfishcode

Cargo.toml

@@ -18,7 +18,8 @@ publish = false
 rustc_version = "0.3.0"
 
 [dev-dependencies]
-async-std = { version = "1.8.0", features = ["attributes"] }
+# Use a git dependency until https://github.com/async-rs/async-std/pull/937 is released.
+async-std = { git = "https://github.com/async-rs/async-std", features = ["attributes"] }
 anyhow = "1.0.37"
 cap-async-std = { path = "cap-async-std", version = "^0.9.1-alpha.0"}
 cap-fs-ext = { path = "cap-fs-ext", version = "^0.9.1-alpha.0"}

cap-async-std/Cargo.toml

@@ -15,9 +15,11 @@ readme = "README.md"
 
 [dependencies]
 arf-strings = { version = "0.3.0", optional = true }
-async-std = { version = "1.8.0", features = ["attributes"] }
+# Enable "unstable" for `spawn_blocking`.
+# Use a git dependency until https://github.com/async-rs/async-std/pull/937 is released.
+async-std = { git = "https://github.com/async-rs/async-std", features = ["attributes", "unstable"] }
 cap-primitives = { path = "../cap-primitives", version = "^0.9.1-alpha.0"}
-unsafe-io = "0.1.0"
+unsafe-io = "0.2.0"
 
 [badges]
 maintenance = { status = "actively-developed" }

cap-async-std/README.md

@@ -15,9 +15,5 @@
 This crate provides a capability-oriented version of [`async-std`]. See the
 [toplevel README.md] for more information about capability-oriented security.
 
-At the moment, `cap-async-std` is a very rudimentary translation of [`cap-std`] to
-`async-std`. It hasn't yet been optimized to make effective use of `async`.
-
 [`async-std`]: https://crates.io/crates/async-std
-[`cap-std`]: https://github.com/bytecodealliance/cap-std/blob/main/cap-std/README.md
 [toplevel README.md]: https://github.com/bytecodealliance/cap-std/blob/main/README.md