Automattic\WP\Cron_Control\Events::reduce_queue PHP Method

    private function reduce_queue($events)
    {
        // Loop through events, adding one of each action during each iteration
        $reduced_queue = array();
        $action_counts = array();
        $i = 1;
        // Intentionally not zero-indexed to facilitate comparisons against $action_counts members
        do {
            // Each time the events array is iterated over, move one instance of an action to the current queue
            foreach ($events as $key => $event) {
                $action = $event['action'];
                // Prime the count
                if (!isset($action_counts[$action])) {
                    $action_counts[$action] = 0;
                }
                // Check and do the move
                if ($action_counts[$action] < $i) {
                    $reduced_queue[] = $event;
                    $action_counts[$action]++;
                    unset($events[$key]);
                }
            }
            // When done with an iteration and events remain, start again from the beginning of the $events array
            if (empty($events)) {
                break;
            } else {
                $i++;
                reset($events);
                continue;
            }
        } while ($i <= 15 && count($reduced_queue) < JOB_QUEUE_SIZE && !empty($events));
        /**
         * IMPORTANT: DO NOT re-sort the $reduced_queue array from this point forward.
         * Doing so defeats the preceding effort.
         *
         * While the events are now out of order with respect to timestamp, they're ordered
         * such that one of each action is run before another of an already-run action.
         * The timestamp mis-ordering is trivial given that we're only dealing with events
         * for the current JOB_QUEUE_WINDOW_IN_SECONDS.
         */
        // Finally, ensure that we don't have more than we need
        if (count($reduced_queue) > JOB_QUEUE_SIZE) {
            $reduced_queue = array_slice($reduced_queue, 0, JOB_QUEUE_SIZE);
        }
        return $reduced_queue;
    }