[SAoC2022] QUIC Protocol : Milestone 1, Part 3 & 4

[Vlad Chicoș]

Hi! I did some more work on my frame/packet reading/writing code. 
My mentor encouraged me to work on an implementation that uses 
D's metaprogramming features. With a single "reader" struct, a 
single "writer" and a set of UDAs I can now encode/decode QUIC 
packets, QUIC frames, TLS frames and TLS extensions, even if each 
one of them has different encoding rules. 
https://github.com/dlang-community/quic-d/pull/4