Put the most important and most frequency accessed struct member first.
diff --git a/Include/setobject.h b/Include/setobject.h
index a14874b..31f2123 100644
--- a/Include/setobject.h
+++ b/Include/setobject.h
@@ -23,8 +23,8 @@
 
 typedef struct {
     /* Cached hash code of the key. */
-    Py_hash_t hash;
     PyObject *key;
+    Py_hash_t hash;
 } setentry;