+extern const u32_t config_minimum_seconds_between_button_presses;
+
+/* Send each report multiple times. Re-sends are sent with exponential delay:
+ * #1 sent immediately
+ * #2 after 1 seconds
+ * #3 after 2 seconds
+ * #4 after 4 seconds
+ * #5 after 8 seconds
+ * ...
+ * #11 after 8 minutes
+ * #12 after 17 minutes
+ * #13 after 34 minutes
+ * #14 after 68 minutes
+ * #15 after 2 hours
+ * #16 after 4 hours
+ * #17 after 9 hours
+ * etc.
+ * This provides some robustness against network outages, automatically
+ * replaying the log periodically to be collected after connectivity
+ * is restored. */
+extern const uint config_resend_count;
+
+/* These control the size of the per-send-count press queues.
+When the button is pressed more than config_maximum_queue_size times
+within the resend interval, some presses will be reported fewer
+than config_resend_count times. This is usually fine because it's
+the old, longest-delyed, most-redundant reports that get dropped;
+fresh, timely reports of new button presses will not get anywhere near
+config_resend_count in a resend interval because the early resend interals
+are so short. */
+extern const uint config_maximum_queue_size;