Challenge: write a reference counted slice that works as much as possible like a built-in slice

[Greg Strong]

On Friday, 12 November 2021 at 01:34:05 UTC, rikki cattermole 
wrote:
> - Any escape hatch must acknowledge that memory lifetimes is 
> not the same thing as the memory containing data of a given 
> type.

I'm sorry, can you expound on this one a little more?  I don't 
follow.