anchor.diff:      Result = ets:insert(?TABLE, {{channel, ChannelId},
                                    os:timestamp()}),
       {reply, Result, State};
  +handle_call({unquarantine_channel, ChannelId}, _From, State)
  +  when is_integer(ChannelId) ->
  +    Result = ets:delete(?TABLE, {channel, ChannelId}),
       {reply, Result, State};
   handle_call(Call, _From, State) ->
       ?WARN("Unexpected call ~p.", [Call]),
  
positive.code:             gen_server:call(Pid, {quarantine_channel, ChannelId})
      end.
  
  %%====================================================================
  %% gen_server callbacks
  %%====================================================================
  
negative.code: -export([start_link/0
           ,channel/1
           ,quarantine_channel/1
           ,unquarantine_channel/1
          ]).
  
  %% gen_server callbacks
  