What you mean is it's a set of C macros, except built-in to the compiler. Great if it's exactly what you need. And you're prepared for severe WTF moments (e.g. equality on map values is ... not the same as equality on variables of the same type containing the same thing). Also, expect the whole thing to be useless if you need slight complexity (e.g. you can use strings as keys, but not bytes (either Bytes, or []byte, but you can use [5]byte for example).

Oh ... you actually need it to be a red-black tree, or a custom hash function ? Tough.