Method get_proxy

src/toml.hpp:7196–7207

		mutable bool proxy_instantiated_ = false;

		TOML_NODISCARD
		proxy_type* get_proxy() const noexcept
		{
			if (!proxy_instantiated_)
			{
				auto p = ::new (static_cast<void*>(proxy_)) proxy_type{ iter_->first, *iter_->second.get() };
				proxy_instantiated_ = true;
				return p;
			}
			else
				return TOML_LAUNDER(reinterpret_cast<proxy_type*>(proxy_));
		}

	  public:
		TOML_NODISCARD_CTOR