Vimbasrc get stuck randomly

[nunzioTarallo]

We have multiple cameras and we use this thread to open and close related streams, sometimes when I close one stream and open another, the execution get stuck.
I realized that putting a sleep just before gst_element_set_state is called, makes vimbasrc run properly.

void MyThread()
{
    GstElement *pipeline;

    GstBus *bus;
    GstMessage *msg;

    gst_init(NULL, NULL);

    std::string lBff;
    lBff = "vimbasrc camera=";
    lBff += cameraCodes[camera_id];
    lBff += " settingsfile=/home/root/1500_384x242.xml ! video/x-raw,format=RGB ! videoconvert ! videoscale ! ";
    lBff += "video/x-raw, format=I420, width=640, height=480 ! queue ! zmqsink endpoint=tcp://127.0.0.1:";
    lBff += std::to_string(50000 + camera_id + 1);

    pipeline = gst_parse_launch(lBff.c_str(), nullptr);


    // Uncommenting the following line it works
     //this_thread::sleep_for (chrono::milliseconds(875));

    gst_element_set_state(pipeline, GST_STATE_PLAYING);

    bus = gst_element_get_bus(pipeline);
    msg = gst_bus_timed_pop_filtered(bus, 25, GST_MESSAGE_ERROR);

    if (msg == nullptr)
        // error handling

    while (Camera_Occurrence_Counter[camera_id])
    {
    }

    if (msg != nullptr)
        gst_message_unref(msg);
    gst_object_unref(bus);
    gst_element_set_state(pipeline, GST_STATE_NULL);
    gst_object_unref(pipeline);
}

Below is the output of debug prints from Gstream configured at level 5:

DEBUG basesrc gstbasesrc.c:3143:gst_base_src_set_allocation:<vimbasrc0> activate pool
DEBUG basesrc gstbasesrc.c:513:gst_base_src_wait_playing_unlocked:<vimbasrc0> live source waiting for running state