Debug CI failures

Author: noteflakes

.github/workflows/test.yml

@@ -32,4 +32,4 @@ jobs:
     - name: Compile C-extension
       run: bundle exec rake compile
     - name: Run tests
-      run:  bundle exec rake test
+      run:  bundle exec ruby test/test_um.rb --verbose

ext/um/um.c

@@ -111,6 +111,8 @@ inline void um_handle_submitted_op_cqe_multi(struct um *machine, struct um_op *o
 }
 
 inline void um_process_cqe(struct um *machine, struct io_uring_cqe *cqe) {
+  printf("process_cqe result: %d\n", cqe->res);
+
   struct um_op *op = (struct um_op *)cqe->user_data;
   if (unlikely(!op)) return;