How we improved DNS record build speed by more than 4,000x

What this post added

Introduced a per-record build system for DNS records, replacing the previous full-zone build approach for most changes. This involved creating a new Kafka event pipeline for record changes, separating the Zone Builder into distinct scheduler types (full-zone and per-record), implementing ordered event processing for per-record builds, and adapting the Quicksilver interface. Addressed bugs related to stale record cleanup during updates, particularly when record names changed, by treating updates as a delete followed by a create.