The three current targets (file, none, stderr) all serialize all of the error data to a string. During development, it would be convenient to be able to define a function that is called with the exception instance. This function might capture additional application state, or open a window in the user's editor, etc.
Note that it is not possible to work around this by replacing report-error itself because the entire clojure.main namespace is AOT-compiled, so alter-var-root has no effect.
See https://github.com/clojure-emacs/cider/issues/3850 for an example where this feature would be helpful.
Related Slack thread: https://clojurians.slack.com/archives/C03S1KBA2/p1779991120304049
