anchor.diff:        % http_request_trace(_),
         % http_request_enq(_),
         % http_request_log(_),
  +      http_request_deq(_),
         up_link_return(Pipe, _)
      ].   
   
  
positive.code: http_request_trace(State) ->
     State.
  
  
negative.code:       http_request_enq(_),
        down_link_egress(Pipe, _),
        % http_request_log(_),
        http_request_deq(_),
        down_link_return(Pipe, _)
     ].   
  
  