Motive behind !empty() with front() instead of Optional front()

[Nick Treleaven]

On Friday, 26 March 2021 at 15:53:39 UTC, Steven Schveighoffer 
wrote:
> Notice that it's an assert, which means it can be removed in 
> correctly-written programs. If you return an Optional, 
> emptiness MUST be checked on every access to an element, even 
> when you know (or have proven) it's not empty.

An optional would have an `unwrap` method for this purpose, which 
also only asserts it is not empty and returns a value.