setup your logging as normal, before the first log message hijack the modules time_to_rotate function. log the first message, replace the original function.

this has (at least) one bug: the first time it will create logfile then rotate it to logfile.1 then create a new logfile. otherwise it should work (assuming i put back the original function correctly).

my $l = get_logger( 'base' );

*old = \&Log::Dispatch::FileRotate::time_to_rotate;
*Log::Dispatch::FileRotate::time_to_rotate = sub { return wantarray ? 
+( 1, 1 ) : 1 };
$l->info('starting up and forcing rotation');
*Log::Dispatch::FileRotate::time_to_rotate = \&old;

$l->info('more logging as usual');
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