A resolver that asks DNS servers with OTP's :inet_res.
It asks with EDNS0 and a 4096-byte UDP payload, since a 2048-bit DKIM key
does not fit in a plain 512-byte answer. :inet_res retries over TCP when an
answer comes back truncated.
Options:
:nameservers: a list of{ip_tuple, port}to ask. The system's servers are the default:timeout: milliseconds for the query, set by the caller
A failure to reach DNS, or a timeout, is :temperror.