anchor.diff:  hash_file(F) ->
       hash_file(F, crypto:sha_init()).
   
  +-spec hash_file(file:io_device(),binary()) -> sha_hash64().
   hash_file(F, Ctx) ->
       case io:get_chars(F, "", ?buf_size) of
           eof ->
  
positive.code: 
  %% @doc Canonicalize an HTTP request path by removing doubled slashes
  %% and trailing slash (except for case of root path).
  canonical_path(Path = <<"/">>) ->
      Path;
  canonical_path(Path) ->
  
negative.code: 
  
  
  -spec(time_iso8601({calendar_date(), calendar_time()} | now) -> binary()).
  %% @doc Converts Erlang time-tuple to iso8601 formatted date string.
  %%
  %% Example output looks like <<"2003-12-13T18:30:02Z">>
  