Because the map keys were converted to []string,
rv.MapIndex(reflect.ValueOf(mapKey)) would panic as it's the "wrong" type (string, instead of the custom string type).
Just keep track of the reflect.Value instead; don't really need to convert it to strings.
Because the map keys were converted to []string, rv.MapIndex(reflect.ValueOf(mapKey)) would panic as it's the "wrong" type (string, instead of the custom string type).
Just keep track of the reflect.Value instead; don't really need to convert it to strings.
Fixes #413