Allow triggering metrics on delegator states.

[hodgestar]

Currently one can't trigger metrics helper metrics on delegator states because those don't have events fired. This is a thorny problem and I'm not entirely sure what the solution is.

[justinvdm]

I'm probably missing some use case, but why would someone want to measure something about a state that doesn't technically exist? For example, if you have a delegate state that delegates to a 'registered' state if someone is registered and a 'register' state if someone isn't registered, you'd maybe want to count the number of people reaching either of those, but I'm not sure why someone would want to count the thing that delegates to them.

[rudigiesler]

For timing metrics, you might want to know how long a user takes to complete a report. It's then easier to start the timer at the delegation state, than to have multiple metrics for each path that the delegation state delegates to. It also means one metric in the dashboard instead of multiple.

[justinvdm]

Ah, there's the use case I was missing, thanks.