Exemplars are representative elements for the stat. For example if a stat min is `30`, we can save one example with that value.
More details about the concept is here: https://grafana.com/docs/grafana/latest/fundamentals/exemplars/
In our context, which save the segment + position in case of min is updated, to make it easier to look after the segment in danger.
Change-Id: I19be482f1ddc7f1711e722c7b17480366d2c8312
