title: How to configure AnyEvent::DNS resolver by default?
body: <p>How to configure <code>AnyEvent::DNS</code> resolver by default, I want to change <code>max_outstanding</code>, <code>reuse</code>, <code>timeout</code>.
  There is an environment variable <code>$ENV{PERL_ANYEVENT_MAX_OUTSTANDING_DNS}</code>, but how to change <code>reuse</code> and <code>timeout</code> ?</p>