src: clean up agent loop when exiting through destructor

Fixes: #22042

PR-URL: #21867
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Eugene Ostroukhov <eostroukhov@google.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>

src/node.cc

@@ -398,10 +398,10 @@ static struct {
   }
 
   void Dispose() {
+    tracing_agent_.reset(nullptr);
     platform_->Shutdown();
     delete platform_;
     platform_ = nullptr;
-    tracing_agent_.reset(nullptr);
   }
 
   void DrainVMTasks(Isolate* isolate) {

src/tracing/agent.cc

@@ -59,6 +59,7 @@ Agent::Agent() {
     Agent* agent = ContainerOf(&Agent::initialize_writer_async_, async);
     agent->InitializeWritersOnThread();
   }), 0);
+  uv_unref(reinterpret_cast<uv_handle_t*>(&initialize_writer_async_));
 }
 
 void Agent::InitializeWritersOnThread() {
@@ -72,6 +73,11 @@ void Agent::InitializeWritersOnThread() {
 }
 
 Agent::~Agent() {
+  categories_.clear();
+  writers_.clear();
+
+  StopTracing();
+
   uv_close(reinterpret_cast<uv_handle_t*>(&initialize_writer_async_), nullptr);
   uv_run(&tracing_loop_, UV_RUN_ONCE);
   CheckedUvLoopClose(&tracing_loop_);