my $tracer = Mail::Log::Trace::Postfix->new({log_file => 't/data/log'});
   my $object = Mail::Log::Trace::Multiple->new();
   $object->add_log( $tracer, sub {} );

   my $condition = {to_address => '<0001@example.com>', from_start => 1};
   ok($object->find_message($condition) , 'Mail::Log::Trace::Multiple: Find message from "to" field.');

   ok($tracer->find_message_info($condition), 'tracer test.');