a fix? at last?

Author: addaleax

src/node_perf.cc

@@ -216,6 +216,7 @@ void MarkGarbageCollectionEnd(Isolate* isolate,
   fprintf(stderr, "shooting into the dark here.\n");
   if (uv_async_init(env->event_loop(), async, PerformanceGCCallback))
     return delete async;
+  uv_unref(reinterpret_cast<uv_handle_t*>(async));
   async->data =
       new PerformanceEntry::Data(env, "gc", "gc",
                                  performance_last_gc_start_mark_,