Ability to track timeEnd in Grafana

[marijnvandevoorde]

Currently, we're recording events in Grafana when a sync is triggered. However, it would be really helpful for us to also record when the sync completes. Grafana has the "timeEnd" property in their Annotations API, but this is currently not implemented:

https://grafana.com/docs/grafana/latest/developers/http_api/annotations/#create-annotation

Thank you!