+ * download and caching for remote resources.
+ * @param find if set to true all matching prefixes will be searched for the
+ * asked resource, if not only the best matching prefix will be used. Note
+ * that the search is performed only if the asked resource is not found in
+ * cache (i.e. to perform the find again you need to clean the cache).
+ * Defaults to false *)
+val filename: ?find:bool -> string -> string