anchor.diff:  intercept(#'queue.bind'{queue = QName} = Method, VHost) ->
       case is_sharded(VHost, QName) of
           true ->
  -            {error, format("Can't bind sharded queue: ~p", [QName])};
  +            precondition_failed("Can't bind sharded queue: ~p", [QName]);
           _    ->
               {ok, Method}
       end;
  
positive.code: intercept(#'queue.unbind'{queue = QName} = Method, VHost) ->
      case is_sharded(VHost, QName) of
          true ->
              {error, format("Can't unbind sharded queue: ~p", [QName])};
          _    ->
              {ok, Method}
      end;
  
negative.code:       fun(Q) ->
                rabbit_amqqueue:info(Q, [consumers])
        end).
  
  precondition_failed(Format, QName) ->
      {precondition_failed,
       format("Error finding sharded queue for: ~p", [QName])}.
  