#  adapted from the Geo::GDAL::FFI docs, untested
my $layer_name = 'some_layer';
my $db = Open('test.gpkg');
my $layer = $dataset->GetLayer($layer_name);
$layer->ResetReading;
while (my $feature = $layer->GetNextFeature) {
    my $value = $feature->GetField('name');
    my $geom = $feature->GetGeomField;
    say $value, ' ', $geom->AsText;
}