@type dns_type() :: :a | :aaaa | :caa | :cname | :gid | :hinfo | :ns | :mb | :md | :mg | :mf | :minfo | :mx | :naptr | :null | :ptr | :soa | :spf | :srv | :txt | :uid | :uinfo | :unspec | :uri | :wks
@spec query_dns(String.t(), dns_type()) :: [ String.t() | {priority :: integer(), String.t()} ]