-callback clunk(fid(), path(), state()) -> result().

-callback create(fid(), path(), Name :: unicode:chardata(), Perm :: e9p:u32(), Mode :: e9p:u8(), state()) ->
                    result({fid(), IOUnit :: e9p:u32()}).

-callback flush(state()) -> result().

-callback init(term()) -> {ok, state()} | {error, Reason :: term()}.

-callback open(fid(), path(), Mode :: integer(), state()) -> result({fid_state(), e9p:u32()}).

-callback read(fid(), path(), Offset :: non_neg_integer(), Length :: non_neg_integer(), state()) ->
                  result({fid_state(), iodata()}).

-callback remove(fid(), path(), state()) -> result().

-callback root(UName :: unicode:chardata(), AName :: unicode:chardata(), state()) ->
                  {ok, fid_state(), state()}.

-callback stat(fid(), path(), state()) -> result(map()).

-callback walk(fid(), File :: unicode:chardata(), unicode:chardata(), state()) -> {fid() | false, state()}.

-callback write(fid(), path(), Offset :: non_neg_integer(), Data :: iodata(), state()) ->
                   result({fid_state(), non_neg_integer()}).

-callback wstat(fid(), path(), map(), state()) -> result().