Expose Packet Decoder？

[thynson]

I'm trying to implement a simple QUIC Load Balancer, following QUIC-LB draft, in Rust.
It would be great if the PartialDecode related symbol can be exposed to the public.

[djc]

Can you make a PR with the changes you need? I'd probably be open to exposing a little more API around this (especially since, based on history, our PartialDecode is unlikely to change much).

[thynson]

I'm implementing it with s2n-quic for now, which already expose its packet decoder. And I'll try it out with quinn later when I finished a prototype.