+ * - resume: int, byte offset to start the download from;
+ * if the server supports ranges
+ * - maxfilesize: int, maximum file size that should be downloaded;
+ * has no effect, if the size of the requested entity is not known
+ * - lastmodified: int, timestamp for If-(Un)Modified-Since header
+ * - timeout: int, seconds the request may take
+ * - connecttimeout: int, seconds the connect may take