Python post-fork handler: exit if grpc shutdown fails
diff --git a/grpc.def b/grpc.def
index 009de4e..72e3e90 100644
--- a/grpc.def
+++ b/grpc.def
@@ -15,6 +15,7 @@
     grpc_register_plugin
     grpc_init
     grpc_shutdown
+    grpc_is_initialized
     grpc_version_string
     grpc_g_stands_for
     grpc_completion_queue_factory_lookup