Create a simulator for tests

[evanxg852000]

Currently, it's hard to test the different stages a node in a cluster can be in. It would be nice to have a kind of simulator built around tokio::task that can start a cluster and simulate packet delay or node failure for testing. look into https://github.com/jepsen-io/maelstrom

[tardunge]

Try madsim https://github.com/madsim-rs/madsim