I'm not a very experienced Rust person, but I suspect the buffer reuse concern could be resolved with a tiny custom allocator, so semantically it's a new buffer on each iteration of the loop, satisfying the borrow checker, but the allocation is free. There are a number of bump/arena/slab allocators that do this, like bumpalo, but it would also be possible to write a small custom one specifically geared toward "just continually reuse this exact pointer".
Anyway, I don't mean to nitpick; I know that what's given in TFA are high level examples representing broader classes of concerns, but I thought this one in particular was interesting for having some decent alternatives.
However, the other issues they mention hit some well-known limitations of Rust, which don't always have a simple satisfactory solution. It's a valid criticism.
With a bit of `unsafe`, it's easy to force through self-referential structs incorrectly and violate exclusive ownership/aliasing rules (that's UB, in Rust!). Sometimes such code can be reorganized to avoid self-referential structs. With enough `unsafe` dark arts it's also possible to properly handle some self-references. However, in general it's typically a false positive in the borrow checker's model, and an annoying limitation.
Anyway, I don't mean to nitpick; I know that what's given in TFA are high level examples representing broader classes of concerns, but I thought this one in particular was interesting for having some decent alternatives.