anchor.diff:              do_note_tap_stats(State, NoteTapTag)
       end,
   
  -    gen_server:enter_loop(?MODULE, [], State2).
  +    gen_server:enter_loop(?MODULE, [], State2, ?HIBERNATE_TIMEOUT).
   
   -define(TAP_STATS_ATTEMPTS, 5).
   do_note_tap_stats(State, NoteTapTag) ->
  
positive.code:   when VBFilterChangeState =/= not_started ->
      ?log_error("Got start_old_vbucket_filter_change request "
                 "from ~p in state `~p`. Refusing.", [Pid, VBFilterChangeState]),
      {reply, refused, State};
  handle_call({start_vbucket_filter_change, _}, {Pid, _} = _From,
              #state{vb_filter_change_state=VBFilterChangeState} = State)
    when VBFilterChangeState =/= not_started ->
      ?log_error("Got start_vbucket_filter_change request "
                 "from ~p in state `~p`. Refusing.", [Pid, VBFilterChangeState]),
      {reply, refused, State};
  handle_call(start_old_vbucket_filter_change, From,
              #state{tap_name=TapName} = State) ->
      ?log_info("Starting old-style vbucket "
  
negative.code: 
  upstream_sender_loop(Upstream) ->
      receive
          hibernate ->
              erlang:hibernate(erlang, apply, [fun upstream_sender_loop/1, [Upstream]]);
          {silence_upstream_new_style, Pid} ->
              Pid ! upstream_silenced,
              erlang:hibernate(erlang, exit, [silenced]);
  