Agree, but I can't recall ever seeing a package in the wild that labels itself as "concurrency-safe" and yet requires the caller to explicitly call Lock! HashM

Agree, but I can't recall ever seeing a package in the wild that labels itself as "concurrency-safe" and yet requires the caller to explicitly call Lock! HashMap is probably a good example https://github.com/cornelk/hashmap https://github.com/cornelk/hashmap