Implementing basic consensus using Raft

Raft is a consensus algorithm that allows distributed systems to keep a shared and managed state (https://raft.github.io/). Setting up a Raft system is complex in many ways, for one you need consensus for an election to occur and succeed. This can be difficult to bootstrap when working with multiple nodes and it can be difficult to get started. A basic cluster can be run on a single node/leader, but if you want redundancy, at least three nodes allows for a single node failure.
This recipe implements a basic in-memory Raft cluster, constructs a state machine that can transition between certain allowed states, and connects the distributed state machine to a web handler that can trigger the transition. This can be useful when you're implementing the base finite state machine interface that Raft requires or when testing. This recipe uses...