Switching between Server processes

[martinduke]

Many server architectures have multiple processes. There are many ways to properly route packets between them, but many have severely limited capabilities.

Add some non-normative text about options here: run QUIC-LB at the demultiplexer, packet toss, register connection IDs at the demultiplexer, or rewrite the CID with the decrypted one at the LB (which has security limitations)