Unable to write metrics to graphite with more than one Event Forwarder

[m4ticode]

While enabling carbon_metrics_endpoint I noticed that the event forwarder always uses the same series to write it's metrics to.

The series is: cb.eventforwarder.*

When we have multiple event forwarders writing to one graphite instance all metrics from all event forwarders will be pushed in the same series rendering the metrics unusable since there is no way to see where these metrics came from in the first place.

Goal: Get the event forwarder to send metrics to graphite starting the series with a unique name i.e. "hostname.cb.eventforwarder.*".

Possible solution: Please provide an option to add a prefix to the metrics being send using the carbon_metrics_endpoint within cb-event-forwarder.conf. I.e. "carbon_metrics_series_prefix=$hostname".