+int32_t next_scheduled_send(press_pile_t *pp);
+
+/* Find a press ready for resend at or before `now`.
+ * Move it out of the press-pile `pp` and into into `press`.
+ * Or return false if there is no press due for re-send. */
+bool get_press_due_for_resend(press_pile_t *pp, uint32_t now, press_t *press);