Book: The Complete Guide to Go Programming Also by me: Thinking in Go (2-book series) — Complete Guide to Go Programming + Hexagonal Architecture in Go My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub You added a tiny functional helpers package to the repo last quarter. Map , Filter , Reduce , GroupBy . Twelve lines each, all generic. The team loved it. Six months later the CI job that used to finish in a handful of minutes is now taking nearly twice that. Nobody admits to a culprit because nobody changed anything obvious. You start bisecting and the line you land on is the import of that helpers package in the third service that pulled it in. Generics in Go are not free. They look free at the call site, which is the whole point. The bill arrives later, in go build wall-clock time and in the size of your release binaries.…