anchor.diff:  	is_conflict(Req, State);
   method(Req, State=#state{method=Method})
   		when Method =:= <<"POST">>; Method =:= <<"PATCH">> ->
  -	accept_resource(Req, State, 204);
  +	accept_resource(Req, State);
   method(Req, State=#state{method=Method})
   		when Method =:= <<"GET">>; Method =:= <<"HEAD">> ->
   	set_resp_body_etag(Req, State);
  
positive.code: 		fun if_match_exists/2, fun if_match_must_not_exist/2).
  
  if_match_exists(Req, State) ->
  	case cowboy_req:parse_header(<<"if-match">>, Req) of
  		{ok, undefined, Req2} ->
  			if_unmodified_since_exists(Req2, State);
  		{ok, '*', Req2} ->
  			if_unmodified_since_exists(Req2, State);
  		{ok, ETagsList, Req2} ->
  			if_match(Req2, State, ETagsList)
  	end.
  
  if_match(Req, State, EtagsList) ->
  
negative.code: 	%% Charset.
  	charsets_p = [] :: [{binary(), integer()}],
  	charset_a :: undefined | binary(),
  
  	%% Whether the resource exists.
  	exists = false :: boolean(),
  
  	%% Cached resource calls.
  	etag :: undefined | no_call | {strong | weak, binary()},
  