Add gh-action and ignores.

.github/workflows/hlint.yml

@@ -0,0 +1,24 @@
+name: hlint
+
+on:
+  pull_request:
+  push:
+
+jobs:
+  build:
+    name: hlint
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - uses: haskell/actions/hlint-setup@v2
+      name: Set up HLint
+      with:
+        version: "3.4"
+
+    - uses: haskell/actions/hlint-run@v2
+      name: hlint
+      with:
+        path: '["unliftio/", "unliftio-core/"]'
+        fail-on: suggestion

.hlint.yaml

@@ -0,0 +1,20 @@
+# Warnings currently triggered by your code
+- ignore: {name: "Avoid lambda"} # 2 hints
+- ignore: {name: "Avoid lambda using `infix`"} # 3 hints
+- ignore: {name: "Eta reduce"} # 1 hint
+- ignore: {name: "Move brackets to avoid $"} # 14 hints
+- ignore: {name: "Redundant bracket"} # 34 hints
+- ignore: {name: "Replace case with maybe"} # 1 hint
+- ignore: {name: "Unused LANGUAGE pragma"} # 12 hints
+- ignore: {name: "Use <$>"} # 2 hints
+- ignore: {name: "Use asum"} # 4 hints
+- ignore: {name: "Use camelCase"} # 19 hints
+- ignore: {name: "Use const"} # 4 hints
+- ignore: {name: "Use even"} # 3 hints
+- ignore: {name: "Use fewer imports"} # 1 hint
+- ignore: {name: "Use fmap"} # 13 hints
+- ignore: {name: "Use lambda-case"} # 1 hint
+- ignore: {name: "Use newTVarIO"} # 3 hints
+- ignore: {name: "Use readTVarIO"} # 8 hints
+- ignore: {name: "Use void"} # 1 hint
+- ignore: {name: "Use when"} # 2 hints