anchor.diff:  %%--------------------------------------------------------------------------
   %% Help functions to handle_ctrl_result
   %%--------------------------------------------------------------------------
  +
  +-spec ctrl_result_response(Status, State, Error) -> Result when
  +      Status :: ctrl_status_operation() | {ctrl_status_operation(), _},
  +      State  :: #state{},
  +      Error  :: {error, Reason},
  +      Reason :: term(),
  +      Result :: {noreply, #state{}} | Error.
   ctrl_result_response(pos_compl, #state{client = From} = State, _)  ->
       gen_server:reply(From, ok),
       {noreply, State#state{client = undefined, caller = undefined}};
  
positive.code: %%    progress
  %%          ftp_extension
  
  open_options(Options) ->
      ValidateMode =
          fun(active) -> true;
  
negative.code: accept_data_connection_tls_options(#state{ tls_options = TO }) ->
  	TO.
  
  -spec accept_data_connection(State) -> Result when
        State  :: #state{},
        Result :: {ok, #state{}} | {error, Reason},
        Reason :: term().
  accept_data_connection(#state{mode     = active,
                                dtimeout = DTimeout,
                                tls_options = TLSOptions0,
  