Add coverage for fiber profiler.

.github/workflows/test-coverage.yaml

@@ -27,8 +27,15 @@ jobs:
             ruby: "3.3"
             selector: EPoll
           - os: ubuntu
-            ruby: "3.3"
+            ruby: "3.4"
+            selector: EPoll
+          - os: ubuntu
+            ruby: "3.4"
+            selector: URing
+          - os: ubuntu
+            ruby: "3.4"
             selector: URing
+            fiber_profile_capture: "true"
           - os: ubuntu
             ruby: "head"
             selector: URing
@@ -51,13 +58,14 @@ jobs:
       env:
         IO_EVENT_SELECTOR: ${{matrix.selector}}
         ASYNC_SCHEDULER_DEFAULT_WORKER_POOL: ${{matrix.worker_pool}}
+        FIBER_PROFILER_CAPTURE: ${{matrix.fiber_profile_capture}}
       run: bundle exec bake test
 
     - uses: actions/upload-artifact@v4
       with:
         include-hidden-files: true
         if-no-files-found: error
-        name: coverage-${{matrix.os}}-${{matrix.ruby}}-${{matrix.selector}}-${{matrix.worker_pool}}
+        name: coverage-${{matrix.os}}-${{matrix.ruby}}-${{matrix.selector}}-${{matrix.worker_pool}}-${{matrix.fiber_profile_capture}}
         path: .covered.db
 
   validate:

gems.rb

@@ -10,7 +10,11 @@
 gemspec
 
 # gem "io-event", git: "https://github.com/socketry/io-event.git"
-gem "fiber-profiler"
+
+# In order to capture both code paths in coverage, we need to optionally load this gem:
+if ENV["FIBER_PROFILER_CAPTURE"]
+	gem "fiber-profiler"
+end
 
 group :maintenance, optional: true do
 	gem "bake-gem"