Can we provide more data when reporting an unhandled rejection?

[BethanyBerkowitz]

See #1172 (comment)

When reporting an unhandled rejection in server-side JS using the plugin, we only provide the "reason".

The "reason" is usually an error, in which case client.notify(reason) should work great. However, the "reason" could also be of some other type. In this case, can we provide more information using the promise passed through in the unhandledRejection event?