code: func MultiResolverOptionWithResolver(r ResolveValidator, tld string) MultiResolverOption {
  	return func(m *MultiResolver) {
  		m.resolvers[tld] = append(m.resolvers[tld], r)
  	}
  }
docs: // MultiResolverOptionWithResolver adds a Resolver to a list of resolvers
  // for a specific TLD. If TLD is an empty string, the resolver will be added
  // to the list of default resolver, the ones that will be used for resolution
  // of addresses which do not have their TLD resolver specified.