my ($tmpdir, $for_destroy) = tmpdir();
my $ibx = create_inbox 'v1', indexlevel => 'medium', tmpdir => "$tmpdir/v1",
pre_cb => sub {
my ($tmpdir, $for_destroy) = tmpdir();
my $ibx = create_inbox 'v1', indexlevel => 'medium', tmpdir => "$tmpdir/v1",
pre_cb => sub {