Can anyone see a problem with using 'F' here?  It appears to be non-standard but I'd like a way to do millisecond-precision logging in the logging library.

Index: date.dylan
===================================================================
--- date.dylan	(revision 12526)
+++ date.dylan	(working copy)
@@ -385,6 +385,8 @@
         'k' => wrap(" ", hours);
         'M' => wrap("0", minutes);
         'S' => wrap("0", seconds);
+        'f' => format-integer(date.date-microseconds, 6);
+        'F' => format-integer(round/(date.date-microseconds, 1000), 3);
 	'T' => concatenate(wrap("0", hours), ":",
                            wrap("0", minutes), ":",
 			   wrap("0", seconds));