Add logging for queue submit and complet counts

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/engines/null.c b/engines/null.c
index 85d6847..eb80501 100644
--- a/engines/null.c
+++ b/engines/null.c
@@ -46,6 +46,7 @@
 	struct null_data *nd = td->io_ops->data;
 
 	if (!nd->events) {
+		io_u_mark_submit(td, nd->queued);
 		nd->events = nd->queued;
 		nd->queued = 0;
 	}