use MCE::Loop chunk_size => 1, max_workers => 5;

my %domainList = mce_loop_f {
    my $domainName = $_;
    chomp $domainName;
    my $expDate = `jwhois -n -h whois.crsnic.net $domainName | grep Expiration | awk '{print \$3}'`;
    my $diff = &dateDiff($expDate);
    if ($diff < 28 and $diff > 14) { $flag = 1; }
    elsif ($diff <= 14) { $flag = 2; }
    MCE->gather($domainName, $diff);
} $domains;