Here's a bit more of a simple example that uses a file handle directly, as opposed to having it hidden in the log object:

use warnings;
use strict;

use Async::Event::Interval;

open my $fh, '>', 'test.log' or die $!;

my $count = 1;

my $e = Async::Event::Interval->new(
    1,
    sub {
        print $fh "in event: $count\n";
        $count++;
    }
);

$e->start;

for (0..3){
    print $fh "write to file in main\n";
    sleep 1;
}

$e->stop;
[download]