Merge remote-tracking branch 'github/ticket25951'

changes/ticket25951

@@ -0,0 +1,9 @@
+  o Minor features (mainloop):
+    - Move responsibility for
+      flushing log callbacks
+      from a once-per-second callback to a callback that is only scheduled as
+      needed.  Once enough items are removed from our once-per-second
+      callback, we can eliminate it entirely to conserve CPU when idle.
+      Closes ticket
+      25951.
+