properties_ = std::make_unique<std::unordered_map<std::string, std::string>>();
std::unordered_map<std::string, std::string> props(std::cbegin(properties), std::cend(properties));
#if __cplusplus >= 201703L
properties_ = std::make_unique<std::unordered_map<std::string, std::string>>();
std::unordered_map<std::string, std::string> props(std::cbegin(properties), std::cend(properties));
#if __cplusplus >= 201703L