anchor.diff:      ?assertNotEqual(timeout, Resp),
       Resp.
   
  -get_heartbeats(Consumer) ->
  +get_heartbeats({Consumer, _}) ->
       Ref = make_ref(),
       Consumer ! {get_heartbeats, Ref},
       Resp = receive
  
positive.code:     ?assertNotEqual(timeout, Resp),
      Resp.
  
  pause(Consumer) ->
      Ref = make_ref(),
      Consumer ! {pause, Ref},
      Resp = receive
  
negative.code:     {ok, Rev} = couch_db:update_doc(Db, Doc, []),
      {ok, couch_doc:rev_to_str(Rev)}.
  
  get_rows({Consumer, _}) ->
      Ref = make_ref(),
      Consumer ! {get_rows, Ref},
      Resp = receive
  