using `buf.starts_with(b"\xAB\xCD")` instead of `buf[0] == 0xAB && buf[1] == 0xCD` is shorter, easier to read, removes the need for the `buf.len() > xyz` check, and actually compiles to (much) less assembly:
https://godbolt.org/z/M7GePGn1T
isn't that just lovely