hmon: add C++ interface to heartbeat monitor

.github/workflows/lint_clippy.yml

@@ -48,8 +48,14 @@ jobs:
           override: true
           components: clippy
 
-      - name: check clippy errors
+      - name: check clippy errors (with "--features stub_supervisor_api_client")
         uses: actions-rs/cargo@v1
         with:
           command: clippy
-          args: --all-features --all-targets --workspace -- -D warnings
+          args: --features stub_supervisor_api_client --all-targets -- -D warnings
+
+      - name: check clippy errors (with "--features score_supervisor_api_client")
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: --features score_supervisor_api_client --no-default-features --all-targets -- -D warnings

.vscode/settings.json

@@ -9,6 +9,9 @@
     "rust-analyzer.cargo.cfgs": [
         "!miri"
     ],
+    "rust-analyzer.cargo.features": [
+        "stub_supervisor_api_client"
+    ],
     "rust-analyzer.check.command": "clippy",
     "rust-analyzer.rustfmt.overrideCommand": [
         "${workspaceFolder}/.vscode/rustfmt.sh"