Mishandled errors inside the 'row success' event callback

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What should be the importer behavior when an exception occurs inside an on :row_success block?

The row was supposedly processed successfully, so exceptions on this event are not captured and sent to the on :row_error handler. Actually, if an exception occurs on the success handler, the importer process ends abnormally, and it shouldn't.

The same problem applies to most if not all of the other callback events, including on :row_processed and on :row_error. How should active_importer handle exceptions occurring inside these event callbacks?