+/* Support for order statistics.
+
+ This data structure supplies infrastructure for higher-level statistics that
+ rely on order statistics. It is a kind of "abstract base class" that is not
+ useful on its own. The common pattern for using the statistics based on it
+ is this:
+
+ - Create the higher-level statistic with, for example, percentile_create().
+
+ - Feed in all the data with order_stats_accumulate() or
+ order_stats_accumulate_idx(). The data must be in sorted order: if
+ necessary, use one of the sorting functions from sort.h to sort them.
+
+ - Obtain the desired results by examining the higher-level data structure or
+ by calling an appropriate function, e.g. percentile_calculate().
+
+ - Destroy the data structure with statistic_destroy().
+*/
+