+ * If 'error' is 0, indicating success, the operation will be committed
+ * permanently to the flow table. There is one interesting subcase:
+ *
+ * - If 'op' is an "add flow" operation that is replacing an existing rule in
+ * the flow table (the "victim" rule) by a new one, then the caller must
+ * have uninitialized any derived state in the victim rule, as in step 5 in
+ * the "Life Cycle" in ofproto/ofproto-provider.h. ofoperation_complete()
+ * performs steps 6 and 7 for the victim rule, most notably by calling its
+ * ->rule_dealloc() function.
+ *
+ * If 'error' is nonzero, then generally the operation will be rolled back:
+ *
+ * - If 'op' is an "add flow" operation, ofproto removes the new rule or
+ * restores the original rule. The caller must have uninitialized any
+ * derived state in the new rule, as in step 5 of in the "Life Cycle" in
+ * ofproto/ofproto-provider.h. ofoperation_complete() performs steps 6 and
+ * and 7 for the new rule, calling its ->rule_dealloc() function.
+ *
+ * - If 'op' is a "modify flow" operation, ofproto restores the original
+ * actions.
+ *
+ * - 'op' must not be a "delete flow" operation. Removing a rule is not
+ * allowed to fail. It must always succeed.