How to start recording while watching

How do I start recording a channel while watching it, and have the recording start from the time I started watching the channel?
There does not seem to be any record options while watching on my iPad, and if I exit watching going back to On Now, I suspect that the viewing buffer is cleared...

There’s no record button in the player on iOS. On the TV clients you swipe down and use the record button in the Quick guide.

Channels can’t apply your buffer to the recording as the buffer is in the client.

OK, thanks.
I seem to recall a discussion about this from before but could not find it when I searched.