+metrics_end_frame (metrics_t *metrics);
+
+/* Process outstanding metrics requests, accumulating results.
+ *
+ * This function is called automatically by metrics_end_frame.
+ *
+ * During a frame, it may be important to call this function to avoid
+ * too many oustanding timer/performance-monitor queries. At the same
+ * time, it's important not to call this function too frequently,
+ * since collection of metrics information will result in flushes of
+ * the OpenGL pipeline which can interfere with the behavior being
+ * measured.
+ */
+void
+metrics_collect_available (metrics_t *metrics);