Raft is moving from TCP/UDP to QUIC in 5.x

[sakno]

Currently, .NEXT Raft implementation provides the following transports:

• HTTP/S
• TCP
• UDP
• Custom

In the next major version (5.x), I have a plan to replace TCP/UDP transports with QUIC protocol due to following reasons:

1. System.Net.Quic will become available in .NET 8 LTS
2. QUIC provides multiplexing while UDP/TCP are not
3. Due to presence of multiplexing, I will able to provide messaging infrastructure for this protocol as it was done for HTTP transport
4. QUIC combines efficiency of UDP and reliable delivery as TCP, plus multiplexing

[sakno]

After detailed analysis, only UDP transport is removed from .NEXT 5.x. QUIC is very questionable because it requires encryption which is impractical for Raft purposes. Typically, cluster nodes communicates between each other in LAN instead of WAN so it is protected by default. In the next release, I'll provide TCP multiplexing without encryption.