template<typename... T>
int context_manager::add_map_context(const T&... args)
{
    map_contexts_.emplace_back(new map_context(args...));
    return map_contexts_.size() - 1;
}

int context_manager::add_map_context(context_ptr&& mc)
{
    map_contexts_.push_back(mc);
    return map_contexts_.size() - 1;
}