how to log all recursive query responses?

[David Sparks]

I wanted to turn on the responses BIND is giving out to recursive queries.  I 
added the below to my named.conf but it didn't do anything.  What does 
resolver log do?

         channel resolver_log {
                 file "/var/log/resolver.log" versions 3 size 100M;
                 severity info;
                 print-category yes;
                 print-severity yes;
                 print-time yes;
         };
         category resolver       { resolver_log; };