Add functions to send and receive unconnected packets in Unity Transport

[SubatomicPlanets]

This is a feature related to the Unity Transport, not Netcode for GameObjects directly, so I don't know if this is the right place.
I want to send and receive packets without any connection. In my specific case, I want to send some data to a server. This server is made in C++ and has nothing to do with Unity. I just want to send something using the socket used by the Unity Transport.

I would like to see a function like .SendTo(message, IPEndPoint) and some way of receiving a response like .ReceiveFrom(IPEndPoint). They could be part of the NetworkDriver.

Right now I am using the Ruffles transport from the multiplayer-community-contributions. Ruffles allows me to send such packets using the .SendRaw function. This is not ideal, as I would like to use the official Unity Transport.

This would also allow an easy implementation of NAT hole punching.

[SubatomicPlanets]

I got it working.

Just in case anyone ever needs this or if anyone would like to know how I did it, here is a simple explanation:

I modified the Unity transport package. I added a function to the NetworkDriver called DirectSend. For receiving I added a new file called DirectDataQueue which you can pop from to get the newest received packet. I also had to modify the SimpleConnectionLayer code a bit.
It isn't a perfect solution but it works well enough in my case. To access the driver in Unity from my own scripts I just made a new script which inherits from UnityTransport and makes the driver public. I could have also just modified the UnityTransport script, but it is in the netcode package and I didn't want to modify another package.

I managed to add NAT punching support with this. By the way, I just did this as a hobby project, not for something I'm going to release. I had to understand the entire Unity Transport code first before doing this but somehow, miraculously, it only took 4 days from starting to read up on the NetworkDriver to having NAT punching implemented.

I will leave this issue open since official support for something like this would be nice, but feel free to close it if you want to.