Yes, will do. 

How about instrumenting `perform_start`, `perform_finish` and `perform_error`? The latter might be more suited as part of the `rescue_from` handling in #25, but I'll put it here for the moment. 

For enqueueing `enqueue` and `enqueue_error` would be enough as `enqueue` would only take a fraction of a second so there's no need for `_start`.

I will check with the rest of the Rails source for naming conventions around instrumentation.

Will send a PR later today.

/cc @dhh