Function gstreamer_rtsp_server_sys::gst_rtsp_client_set_send_messages_func

pub unsafe extern "C" fn gst_rtsp_client_set_send_messages_func(
    client: *mut GstRTSPClient, 
    func: GstRTSPClientSendMessagesFunc, 
    user_data: gpointer, 
    notify: GDestroyNotify
)

This is supported on crate feature v1_16 only.