-spec get_info(binary()) -> {ok, map()} | {error, not_found}.

-spec handle_call(term(), gen_server:from(), map()) -> {reply, term(), map()}.

-spec handle_cast(term(), map()) -> {noreply, map()}.

-spec handle_info(term(), map()) -> {noreply, map()} | {stop, normal, map()}.

-spec init(map()) -> {ok, map()}.

-spec join(binary(), binary()) -> ok | {error, term()}.

-spec start_link(map()) -> gen_server:start_ret().

-spec terminate(term(), map()) -> ok.