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: main.rs
    path of file: ./repos/tfs/lz4/src
    
    the code of the file until where you have to start completion: extern crate lz4_compress as lz4;

use std::{env, process};
use std::io::{self, Write, Read};

/// The help page for this command.
const HELP: &'static [u8] = br#"
Introduction:
    lz4 - an utility to decompress or compress a raw, headerless LZ4 stream.
Usage:
    lz4 [option]
Options:
    -c : Compress stdin and write the result to stdout.
    -d : Decompress stdin and write the result to stdout.
    -h : Write this manpage to stderr.
"#;

fn main() {
    let mut iter = env::args().skip(1);
    let mut flag = iter.next().unwrap_or(String::new());
    // If another argument is provided (e.g. the user passes a file name), we need to make sure we
    // issue an error properly, so we set back the flag to `""`.
    if iter.next().is_some() {
        flag = String::new();
    }

    match &*flag {
        "-c" => {
            // Read stream from stdin.
            let mut vec = Vec::new();
            io::stdin().read_to_end(&mut vec).expect("Failed to read stdin");

            // Compress it and write the result to stdout.
            io::stdout().write(&lz4::compress(&vec)).expect("Failed to write to stdout");
        },
        "-d" => {
            // Read stream from stdin.
            let mut vec = Vec::new();
            io::stdin().read_to_end(&mut vec).expect("Failed to read stdin
    
fn main() {
    let mut iter = env::args().skip(1);
    let mut flag = iter.next().unwrap_or(String::new());
    // If another argument is provided (e.g. the user passes a file name), we need to make sure we
    // issue an error properly, so we set back the flag to `""`.
    if iter.next().is_some() {
        flag = String::new();
    }

    match &*flag {
        "-c" => {
            // Read stream from stdin.
            let mut vec = Vec::new();
            io::stdin().read_to_end(&mut vec).expect("Failed to read stdin");

            // Compress it and write the result to stdout.
            io::stdout().write(&lz4::compress(&vec)).expect("Failed to write to stdout");
        },
        "-d" => {
            // Read stream from stdin.
            let mut vec = Vec::new();
            io::stdin().read_to_end(&mut vec).expect("Failed to read stdin");

            // Decompress the input.
            let decompressed = lz4::decompress(&vec).expect("Compressed data contains errors");

            // Write the decompressed buffer to stdout.
            io::stdout().write(&decompressed).expect("Failed to write to stdout");
        },
        // If no valid arguments are given, we print the help page.
        _ => {
            io::stdout().write(HELP).expect("Failed to write to stdout");

            process::exit(1);
        },
    }
}