You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: magic_numbers.rs
    path of file: ./repos/broot/src/content_type
    
    the code of the file until where you have to start completion: 
use {
    phf::{phf_set, Set},
    std::{
        path::Path,
        fs::File,
        io::{self, Read},
    },
};

pub const MIN_FILE_SIZE: usize = 100;

// those ones are now removed because of the extension filtering
// static SIGNATURES_2: [[u8;2];2] = [
//     [ 0x4D, 0x5A ], // exe, dll
//     [ 0x42, 0x4D ], // BMP - Is that still necessary ?
// ];

// those ones are now removed because of the extension filtering
// static SIGNATURES_3: [[u8;3];2] = [
//     [ 0x49, 0x44, 0x33 ], // mp3
//     [ 0x77, 0x4F, 0x46 ],  // WOFF
// ];

// signatures starting with 00, FF or FE don't need to be put here
// note: the phf_set macro doesn't seem to allow u32 literals like 0x504B0304
static SIGNATURES_4: Set<[u8; 4]> = phf_set! {
  
    
pub fn is_known_binary(bytes: &[u8]) -> bool {
    if bytes.len() < 4 {
        return false;
    }
    let c = bytes[0];
    if c < 9 || (c > 13 && c < 32) || c >= 254 {
        // c < 9 include several signatures
        // 14 to 31 includes several signatures among them some variants of zip, gzip, etc.
        // FE is "þ", FF is "ÿ"
        // the FE/FF cases includes several signatures like Mach-O, jpeg or mpeg
        // TODO Some non ASCII UTF-8 chars start with FE or FF - check it's OK
        return true;
    }
    // for signature in &SIGNATURES_2 {
    //     if signature == &bytes[0..2] {
    //         return true;
    //     }
    // }
    // for signature in &SIGNATURES_3 {
    //     if signature == &bytes[0..3] {
    //         return true;
    //     }
    // }
    if SIGNATURES_4.contains(&bytes[0..4]) {
        return true;
    }
    // for signature in &SIGNATURES_5 {
    //     if signature == &bytes[0..5] {
    //         return true;
    //     }
    // }
    // for signature in &SIGNATURES_6 {
    //     if signature == &bytes[0..6] {
    //         return true;
    //     }
    // }
    false
}