How to make a [u8; 11] out of "hello world"?

This works:

pub const HELLO_WORLD: [u8] = "hello world".to_string().as_bytes();

but I need it to be a [u8; 11] so that I can do simple byte matches, such as:

if buf[4..15] != HELLO_WORLD {

(This is to check "magic" strings in a file format.)

Is there a way of declaring:

pub const HELLO_WORLD: [u8; 11] = "hello world".to_string().as_bytes();

that does not cause an error? (An &[u8; 11] would also be fine, it's having a type with a fixed length which is important.)

Rust has byte string literals, which are similar to string literals but prefixed with a b. b"hello world" will give you a &[u8; 11].