void
 async_resolve (
     implementation_type &impl,
     const string & domain,
     const net::dns::type_t rrtype,
     CallbackHandler handler )
 {
   net::dns::question question(domain, rrtype);
   impl->async_resolve(question, handler);
 }
 void
 async_resolve ( implementation_type &impl, const net::dns::question & question, CallbackHandler handler )
 {
   impl->async_resolve(question, handler);
 }