anchor.diff:      ?assertNotEqual(timeout, Resp),
       Resp.
   
  -pause(Consumer) ->
  +pause({Consumer, _}) ->
       Ref = make_ref(),
       Consumer ! {pause, Ref},
       Resp = receive
  
positive.code:     ?assertNotEqual(timeout, Resp),
      Resp.
  
  unpause(Consumer) ->
      Ref = make_ref(),
      Consumer ! {continue, Ref},
      Resp = receive
  
negative.code:     ?assertNotEqual(timeout, Resp),
      Resp.
  
  stop_consumer({Consumer, _}) ->
      Ref = make_ref(),
      Consumer ! {stop, Ref},
      Resp = receive
  