Ways to enable logging:
1) Set git's trace2.eventtarget config variable to desired logging path
2) Specify path via --git_trace2_event_log option
A unique logfile name is generated per repo execution (based on the repo session-id).
Testing:
1) Verified git config 'trace2.eventtarget' and flag enable logging.
2) Verified version/start/end events are expected format:
https://git-scm.com/docs/api-trace2#_event_format
3) Unit tests
Bug: https://crbug.com/gerrit/13706
Change-Id: I335eba68124055321c4149979bec36ac16ef81eb
Tested-by: Ian Kasprzak <iankaz@google.com>
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/292262
Reviewed-by: Mike Frysinger <vapier@google.com>
Reviewed-by: Jonathan Nieder <jrn@google.com>
