Remove dependency on `std` for `async` feature #3865

Job	Run time
Rustfmt	13s
Check	2m 40s
Test Async (allowed to fail)	2m 45s
Crate Unit Tests	2m 46s
clippy	56s
verify-publish	2m 45s
Build wit-bindgen (x86_64-windows, windows-latest, x86_64-pc-windows-msvc, -Ctarget-feature=+crt-...	4m 44s
Build wit-bindgen (x86_64-macos, macos-latest, x86_64-apple-darwin, 10.12)	2m 32s
Build wit-bindgen (aarch64-linux, ubuntu-latest, aarch64-unknown-linux-gnu, ./ci/docker/aarch64-l...	3m 3s
Build wit-bindgen (riscv64gc-linux, ubuntu-latest, riscv64gc-unknown-linux-gnu, ./ci/docker/riscv...	2m 55s
Build wit-bindgen (x86_64-linux, ubuntu-latest, x86_64-unknown-linux-gnu, ./ci/docker/x86_64-linu...	2m 49s
Build wit-bindgen (aarch64-macos, macos-latest, aarch64-apple-darwin, 10.12)	2m 33s
Build wit-bindgen (aarch64-windows, windows-11-arm, aarch64-pc-windows-msvc, -Ctarget-feature=+cr...	4m 19s
Test (ubuntu-latest, c)	1m 58s
Test (macos-latest, rust)	3m 32s
Test (ubuntu-latest, cpp)	3m 28s
Test (ubuntu-latest, go)	4m 1s
Test (macos-latest, c)	2m 6s
Test (macos-latest, cpp)	2m 55s
Test (windows-latest, c)	4m 45s
Test (ubuntu-latest, csharp)	5m 19s
Test (macos-latest, go)	4m 19s
Test (ubuntu-latest, rust)	3m 1s
Test (windows-latest, csharp)	4m 46s
Test (windows-latest, rust)	4m 44s
Test (windows-latest, go)	4m 46s
Test (windows-latest, cpp)	4m 35s
Record the result of testing and building steps	3s
	1h 29m 18s

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