EVENT_IPE payload length can easily overflow
Problem: EVENT_IPE has a payload length which is Word16, hence limit 65536. This can overflow if there are very long string fields in IPE info.
However, I don't know why this field exists because it's not needed to decode the payload.
Also see !11767 (closed) which is related to this but would truncate each string to size Word16 (still not sufficient to fix this overflow).
This caused an issue in ghc-events
where the assertion failed which checked the payload size matched up with what was actually parsed.