[jerf]

I'm not deeply familiar with those C# types, but I think maybe it already does. An array, which includes the size of itself in its type so that a four-element array is not the same type as an eight-element array, is already in Go. Go's language affordances make it easy to just have slices without the underlying arrays, since they're generally not useful on their own, but you can take arrays and slice into them if you like.