$im = PublicInbox::V2Writable->new($ibx, {nproc => 2});
is($im->{shards}, 1, 'detected single shard from previous');
my ($mark, $rm_mime, $smsg) = $im->remove($mime, 'test removal');
$im = PublicInbox::V2Writable->new($ibx, {nproc => 2});
is($im->{shards}, 1, 'detected single shard from previous');
my ($mark, $rm_mime, $smsg) = $im->remove($mime, 'test removal');