+
+ /* This subfacet should conceptually be created, and have its first
+ * packet pass through, at the same time that its facet was created.
+ * If we called time_msec() here, then the subfacet could look
+ * (occasionally) as though it was used some time after the facet was
+ * used. That can make a one-packet flow look like it has a nonzero
+ * duration, which looks odd in e.g. NetFlow statistics. */
+ subfacet->used = facet->used;