Uses of https://golang.org/pkg/sync/#Map https://golang.org/pkg/sync/#Map are objectively harder to read than if they allowed a library to implement a type that

Uses of https://golang.org/pkg/sync/#Map https://golang.org/pkg/sync/#Map are objectively harder to read than if they allowed a library to implement a type that conforms to builtin map[K]V. Instead you have to learn method names and cast return values, and builtin maps don't even support those methods.