-spec delete_value(SessionId :: binary()) -> ok | {error, Reason :: term()}.

-spec delete_value(SessionId :: binary(), Key :: binary()) -> ok | {error, Reason :: term()}.

-spec get_value(SessionId :: binary(), Key :: binary()) -> {ok, Value :: binary()} | {error, not_found}.

-spec set_value(SessionId :: binary(), Key :: binary(), Value :: binary()) ->
             ok | {error, Reason :: term()}.

-spec start_link() ->
              {ok, Pid :: pid()} |
              {error, Error :: {already_started, pid()}} |
              {error, Error :: term()} |
              ignore.