How many years of commercial experience do you have in Go?

Commercial experience working with Go is usually measured in years and depends on specific projects and companies. For example, if you have worked in production with Go for 2-3 years, this is considered good experience for a middle+ level. Not only the number of years is important, but also the depth of understanding of the language, experience working with its ecosystem such as goroutines, channels, the standard library, as well as experience writing efficient and maintainable code.