> I can understand when you need the absolute best performance and you decide to drop to down to C++
Could you help me understand with an example or two? My understanding is that well written Rust and C++ are often identical in performance thanks to relying on the same compiler backend (both clang and rustc use LLVM).
Even, possibly, the other way around in some cases. A seemingly identical program may (and it does occur) compile to a faster machine code in rust than in C++ due to extra markers (eg alignment) that rust compiler is able to provide to llvm.