anchor.diff:  %% start: ./erl_expect -sname ejabberd@sdb-ali-hangzhou-ejabberd3 -setcookie 'LTBEXKHWOCIRRSEUNSYS' common/lager_event_watcher.erl start
   %% stop ./erl_expect -sname ejabberd@sdb-ali-hangzhou-ejabberd3 -setcookie 'LTBEXKHWOCIRRSEUNSYS' common/lager_event_watcher.erl stop
   %% get_state ./erl_expect -sname ejabberd@sdb-ali-hangzhou-ejabberd3 -setcookie 'LTBEXKHWOCIRRSEUNSYS' common/lager_event_watcher.erl get_state
  -%% set ./erl_expect -sname ejabberd@sdb-ali-hangzhou-ejabberd3 -setcookie 'LTBEXKHWOCIRRSEUNSYS' common/lager_event_watcher.erl threshold|interval|marks_len|reboot_after N
  +%% set ./erl_expect -sname ejabberd@sdb-ali-hangzhou-ejabberd3 -setcookie 'LTBEXKHWOCIRRSEUNSYS' common/lager_event_watcher.erl threshold|interval|max_over_cnt|reboot_after N
   %% e.g.
   %% ./erl_expect -sname ejabberd@sdb-ali-hangzhou-ejabberd3 -setcookie 'LTBEXKHWOCIRRSEUNSYS' common/lager_event_watcher.erl threshold 1000
   
  
positive.code:         lager_event_watcher:get_state();
      [Key, Value] when Key == "threshold";
                        Key == "interval"
                        Key == "marks_len" 
                        Key == "reboot_after" ->
          try list_to_integer(Value) of
              N ->
  
negative.code:     ["start"] ->
          Threshold = application:get_env(lager, event_watcher_threshold, 1000),
          Interval = application:get_env(lager, event_watcher_interval, 1000),
          MaxOverCnt = application:get_env(lager, event_watcher_max_over_cnt, 3),
          RebootAfter = application:get_env(lager, event_watcher_reboot_after, 5000),
  
          Watcher = {lager_event_watcher, {lager_event_watcher, start_link, 
                                           [Threshold, Interval, MaxOverCnt, RebootAfter]},
                     permanent, 5000, worker, [lager_event_watcher]},
          
          supervisor:terminate_child(lager_sup, lager_event_watcher),
  