bpo-36356: Fix memory leak in _asynciomodule.c (GH-16598)

diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index b67afd4..89b2fde 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -33,6 +33,7 @@
 static PyObject *asyncio_InvalidStateError;
 static PyObject *asyncio_CancelledError;
 static PyObject *context_kwname;
+static int module_initialized;
 
 static PyObject *cached_running_holder;
 static volatile uint64_t cached_running_holder_tsid;
@@ -3247,6 +3248,12 @@
     if (asyncio_mod == NULL) {
         goto fail;
     }
+    if (module_initialized != 0) {
+        return 0;
+    } 
+    else {
+        module_initialized = 1;
+    }
 
     current_tasks = PyDict_New();
     if (current_tasks == NULL) {