I Tried to Find Out How ClickHouse Keeper Takes Non-Blocking Snapshots

This is a continuation from my previous post here: I've been putting together some notes/videos/blog posts - partly for my own future reference and partly to share with others who might find it useful. Would love feedback and corrections from people who know this stuff deeply. The corresponding blog post for the same: thewalstreetjournal.github.io/posts/clickhouse-keeper-non-blocking-snapshots