MLIOSBond

`std::optional` instead of `std::tuple`

1

I assume that this library is based on C++17 (by using [`std::variant`](https://github.com/amyhaber/libdnspacket/blob/master/dns.hpp#L11)) — so wouldn't it be better to replace `std::tuple` with `std::optional` in the [`Parse`](https://github.com/amyhaber/libdnspacket/blob/cf6775a3e97bc8ee220e7590ca5f6e08a085bcc2/dns.hpp#L960) function? Suggestion: ```cpp std::optional...