Another source of time for the logging package?

[Skip Montanaro]

I have code I run in both live and historical modes.  When running in
historical mode the input stream is a set of stored event sequences that
have their own timestamps.  When picking through the logfiles for a
particular run, I'd much prefer it if the timestamps in the logfile
generated with the logging package corresponded to the timestamps on the
stored events, not to wall clock time.  Looking at the code for the logging
package it's far from obvious that this is possible without some surgery.
Before I get out my scalpel, has anyone found a non-invasive way to do this
(or already done the surgery and would be willing to share it)?

Thanks,

Skip