{
    use esmith::AccountsDB;

    $accountsdb = esmith::AccountsDB->open_ro;

    sub compute_default_concur
    {
        # Number of users, + admin who doesn't show up in the users method.
        my $nusers = scalar $accountsdb->users + 1;
        my $multiplier = $imaps{ConcurrencyMultiple} || 4;
        return $nusers * $multiplier;
    }

    my $concurrency = $imaps{ConcurrencyLimit} || compute_default_concur();
    "$concurrency";
}
