Countries - ISO-639, ISO-3166 countries codes with subdivisions and names, ISO-4217 currency designators, ITU-T E.164 IDD phone codes, countries capitals, UN M.49 codes, IANA ccTLD countries domains, FIPS, IOC/NOC and FIFA codes, VERY VERY FAST, compatible with Databases/JSON/BSON/GOB/XML/CSV, Emoji countries flags and currencies, Unicode CLDR.
Why do you think that https://github.com/pkg/errors is a good alternative to countries