Oxy: Fish/Bumblebee/Splicer subsystems to improve reliability

What this post added

This post details the implementation of graceful upgrades within the Oxy framework by splitting a large proxy process into smaller, specialized microservices (Splicer, Bumblebee, Fish). It explains how these services leverage Unix Domain Sockets and file descriptor passing (SCM_RIGHTS) to maintain state and connections across process restarts. The post also elaborates on using Tokio's JoinSet for managing concurrent tasks and implementing cancellation for graceful state transfer during upgrades.