The field `__msg_cbytes` is defined in the structure `msqid_ds`, but it is kept **private**. I need access to that field. Target triple: `x86_64-unknown-linux-gnu`. Reproducer: [here](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=0456874c396614c6fec61201d5a189d4).
