So thanks again! and this will really help a lot of people.
I'd like to echo this thanks to you all.
While looking to add support for SERIALIZE in an explain visualisation tool I work on, I realised there isn't yet an equivalent auto_explain parameter for SERIALIZE. I'm not sure if this is a deliberate omission (perhaps for a similar reason planning time is not included in auto_explain?), but I didn't see it mentioned above, so I thought best to ask in case not.