inline bool encode_geometry(mapnik::geometry::linear_ring<std::int64_t> const& ring,
                        vector_tile::Tile_Feature & current_feature,
                        int32_t & start_x,
                        int32_t & start_y)
{
    std::size_t ring_size = ring.size();
    if (ring_size < 3)
    {
        return false;
    }
    unsigned line_to_length = static_cast<unsigned>(ring_size) - 1;
    unsigned count = 0;
    enum {
        move_to = 1,
        line_to = 2,
        coords = 3
    } status = move_to;
    bool drop_last = false;
    if (ring.size() > 2 && ring.front() == ring.back())
    {
        drop_last = true;
        line_to_length -= 1;
        if (line_to_length < 2)
        {
            return false;
        }
    }

    for (auto const& pt : ring)
    {
        if (status == move_to)
        {
            status = line_to;
            current_feature.add_geometry(9); // 1 | (move_to << 3)
        }
        else if (status == line_to)
        {
            status = coords;
            current_feature.add_geometry(encode_length(line_to_length));
        }
        else if (drop_last && count == line_to_length + 1)
        {
            continue;
        }
        int32_t dx = pt.x - start_x;
        int32_t dy = pt.y - start_y;
        // Manual zigzag encoding.
        current_feature.add_geometry(protozero::encode_zigzag32(dx));
        current_feature.add_geometry(protozero::encode_zigzag32(dy));
        start_x = pt.x;
        start_y = pt.y;
        ++count;
    }
    current_feature.add_geometry(15); // close_path
    return true;
}
    void operator() (mapnik::geometry::linear_ring<T> const& lr1, mapnik::geometry::linear_ring<T> const& lr2)
    {
        if (lr1.size() != lr2.size())
        {
            REQUIRE(false);
        }

        for(auto const& p : zip_crange(lr1, lr2))
        {
            REQUIRE(p.template get<0>().x == Approx(p.template get<1>().x));
            REQUIRE(p.template get<0>().y == Approx(p.template get<1>().y));
        }
    }