Function gstreamer_rtsp_server_sys::gst_rtsp_onvif_media_factory_get_backchannel_launch

pub unsafe extern "C" fn gst_rtsp_onvif_media_factory_get_backchannel_launch(
    factory: *mut GstRTSPOnvifMediaFactory
) -> *mut c_char

This is supported on crate feature v1_14 only.