require PublicInbox::V2Writable;
$im = PublicInbox::V2Writable->new($ibx);
$im->{parallel} = 0; # pointless to be parallel for a single message
require PublicInbox::V2Writable;
$im = PublicInbox::V2Writable->new($ibx);
$im->{parallel} = 0; # pointless to be parallel for a single message