The only parts of this that I (as someone who has dabbled in rust, but barely interacted with explicit lifetimes, ever) am confused by is
"&()".
And I assume it is similar to some kind of implicit capture group in cpp ("[&]") and "`_", which is a lifetime of some kind. I don't know what the "use" keyword does, but it's not a sigil, and "->", "impl Sized", and "{"/"}" are all fairly self-explanatory.
It's a reference to a unit type. unit is pretty useless (like void in Java). It's sort of a silly thing you wouldn't do in real production code, just whoever wrote this example picked a type that is short to type, would be understood by a Rust programmer, and doesn't require any external context.
It would need to be &u8, as without a reference, you won't have any captured lifetimes, and therefore it wouldn't serve as an example for the capturing lifetime feature. &u8 is also a mostly pointless type in reality.
"&()".
And I assume it is similar to some kind of implicit capture group in cpp ("[&]") and "`_", which is a lifetime of some kind. I don't know what the "use" keyword does, but it's not a sigil, and "->", "impl Sized", and "{"/"}" are all fairly self-explanatory.
I will say https://doc.rust-lang.org/edition-guide/rust-2024/rpit-lifet... does not answer any of my questions and only creates more.