Motivations
-----------
DnsNameResolverBuilder and DnsNameResolver do not auto-configure
themselves uing default options define in /etc/resolv.conf.
In particular, rotate, timeout and attempts options are ignored.
Modifications
-------------
- Modified UnixResolverDnsServerAddressStreamProvider to parse ndots,
attempts and timeout options all at once and use these defaults to
configure DnsNameResolver when values are not provided by the
DnsNameResolverBuilder.
- When rotate option is specified, the DnsServerAddresses returned by
UnixResolverDnsServerAddressStreamProvider is rotational.
- Amend resolv.conf options with the RES_OPTIONS environment variable
when present.
Result:
Fixes https://github.com/netty/netty/issues/10202
4f72cdf233