+For network streaming, we need two URL for the control and data stream. Using
+the net(6) protocol for the ctrl_url, the data_url argument is ignored. The
+_ctrl_url_ MUST never be NULL or else an error is returned. If the _data_url_
+is NULL, the ctrl url is used.
+
+For both functions (consumer and create), the _*url_ will be parsed into a