lib/DBMerge.pm 

has unconverted => (
    is      => 'ro',
    lazy    => 1,
    builder => '_build_unconverted',
);

has 'errors' => (
    traits  => ['Counter'],
    is      => 'ro',
    isa     => 'Num',
    default => 0,
    handles => {
        inc_errors   => 'inc',
    },
);