Ask HN: What rabbit hole(s) did you dive into recently?

The reason why I want to learn more about it is I feel it is like a base building block of distributed systems and may be easier to grok and even write a toy version than a bigger thing like kubernetes or a leaderless distributed datastore. I would also learn some go and know how a critical piece of kubernetes works.

What led me there is practicing for a damn system design interview. As much as this whole topic is controversial on HN the grinding has really got me curious about the tech that runs at larger scales and how it works under the hood.