set up code coverage

.github/workflows/rust.yml

@@ -30,3 +30,33 @@ jobs:
       run: cargo build --verbose
     - name: Run tests
       run: cargo test --verbose
+
+  coverage:
+    name: Coverage
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v2
+      - name: Install rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          override: true
+      - name: Cache
+        uses: Swatinem/rust-cache@v1
+      - name: Install cargo-tarpaulin
+        uses: actions-rs/cargo@v1
+        with:
+          command: install
+          args: cargo-tarpaulin
+      - name: Run cargo tarpaulin
+        uses: actions-rs/cargo@v1
+        with:
+          command: tarpaulin
+          args: --output-dir coverage --out xml --workspace --tests --example log --example rfc5424 --example write
+      - name: Upload coverage reports to Codecov
+        uses: codecov/codecov-action@v4.0.1
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          slug: Geal/rust-syslog