ci(rust.yml): add workflow testing feature permutations

Author: mxinden

.github/workflows/rust.yml

@@ -149,3 +149,16 @@ jobs:
         api-level: ${{ matrix.api-level }}
         arch: ${{ matrix.emulator-arch }}
         script: .github/workflows/rust-android-run-tests-on-emulator.sh
+
+  features:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    env:
+      RUSTFLAGS: -Dwarnings
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: taiki-e/install-action@cargo-hack
+      - run: cargo hack check --feature-powerset --optional-deps --no-dev-deps --ignore-unknown-features --ignore-private --group-features runtime-async-std,async-io,async-std --group-features runtime-smol,async-io,smol