diff --git a/cpp/types.h b/cpp/types.h
index 906ff1c..8c31a57 100644
--- a/cpp/types.h
+++ b/cpp/types.h
@@ -16,6 +16,7 @@ namespace f8
         a8::XObject request;
         a8::MutableXObject* resp_xobj = nullptr;
 
+        int async_pending_count = 0;
         void* context = nullptr;
         void (*free_context)(void*) = nullptr;