pub struct Keys {
    pub keys: [u8; std::u32::MAX as usize],
}

impl Default for Keys {
    fn default() -> Self {
        Self {
            keys: unsafe {
                let mut arr: [u8; std::u32::MAX as usize] = std::mem::uninitialized();
                for item in &mut arr[..] {
                    std::ptr::write(item, 0);
                }
                arr
            },
        }
    }
}

fn main() {
    let input_keys = Keys::default();

    assert_eq!(input_keys.keys[14], 0);
}