a timeout in microseconds
gstrtsp.types.RTSPResult.Ok when if there is room in queue. gstrtsp.types.RTSPResult.Etimeout when timeout was reached. gstrtsp.types.RTSPResult.Eintr when watch is flushing gstrtsp.types.RTSPResult.Einval when called with invalid parameters.
Wait until there is place in the backlog queue, timeout is reached or watch is set to flushing.
If timeout is 0 this function can block forever. If timeout contains a valid timeout, this function will return gstrtsp.types.RTSPResult.Etimeout after the timeout expired.
The typically use of this function is when gst_rtsp_watch_write_data returns gstrtsp.types.RTSPResult.Enomem. The caller then calls this function to wait for free space in the backlog queue and try again.