MemoryPack support

[HavenDV]

https://github.com/Cysharp/MemoryPack

[michalpaukert]

Does it support derived types serialization or should i implement some convertor?

[HavenDV]

I learned about this yesterday as the next level of development for MessagePack (which we already support), so it makes sense to have support for it.
We need to implement a Formatter for this and I think it's pretty trivial.
That being said, I don't know anything at the moment about the intricacies of use and whether this supports inherited types, but I think this case is supported because the documentation looks pretty solid