Your example is too simple, GoLang is easy to learn and use, that was one of its design objectives. A professional SW Engineer can be proficient in the language

Your example is too simple, GoLang is easy to learn and use, that was one of its design objectives. A professional SW Engineer can be proficient in the language in couple of days. But from your question I get that you need to be able to get a rough estimate how much time it will take to learn the specific technology. And if it's too long, maybe abandon the idea altogether. It's especially relevant if you're doing it part time or after your main job.