+ /* Prepare to ask the datapath for statistics on 'rule', or if it is
+ * wildcarded then on all of its subrules.
+ *
+ * Also, add any statistics that are not tracked by the datapath for each
+ * subrule. This includes, for example, statistics for packets that were
+ * executed "by hand" by ofproto via dpif_execute() but must be accounted
+ * to a flow. */