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: mod.rs
    path of file: ./repos/boringtun/boringtun/src/noise
    
    the code of the file until where you have to start completion: // Copyright (c) 2019 Cloudflare, Inc. All rights reserved.
// SPD
    
    fn create_ipv4_udp_packet() -> Vec<u8> {
        let header =
            etherparse::PacketBuilder::ipv4([192, 168, 1, 2], [192, 168, 1, 3], 5).udp(5678, 23);
        let payload = [0, 1, 2, 3];
        let mut packet = Vec::<u8>::with_capacity(header.size(payload.len()));
        header.write(&mut packet, &payload).unwrap();
        packet
    }