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: userspace.rs
    path of file: ./repos/nebulet/tools/src/bin
    
    the code of the file until where you have to start completion: extern crate tar;
extern crate walkdir;

use walkdir::WalkDir;
use std::process::Command;
use std::fs::File;
use std::io;

fn main() -> io::Result<()> {
    println!("Building userspace");

    Command::new("cargo")
        .args(&[
            "build",
            "--manifest-path", "userspace/Cargo.toml",
            "--release",
            "--target", "wasm32-unknown-unknown"
        ])
        .status()
        .expect("Failed to build userspace");

    println!("Building initfs.tar");

    let file = File::create("initfs.tar")?;
    let mut tar = tar::Builder::new(file);
    tar.mode(tar::HeaderMode::Deterministic);

    for entry in WalkDir::new("initfs").into_iter().filter_map(|e| e.ok()) {
        if entry.file_type().is_file() {
            let name = entry.file_name().to_str().unwrap();
            printl
    
fn main() -> io::Result<()> {
    println!("Building userspace");

    Command::new("cargo")
        .args(&[
            "build",
            "--manifest-path", "userspace/Cargo.toml",
            "--release",
            "--target", "wasm32-unknown-unknown"
        ])
        .status()
        .expect("Failed to build userspace");

    println!("Building initfs.tar");

    let file = File::create("initfs.tar")?;
    let mut tar = tar::Builder::new(file);
    tar.mode(tar::HeaderMode::Deterministic);

    for entry in WalkDir::new("initfs").into_iter().filter_map(|e| e.ok()) {
        if entry.file_type().is_file() {
            let name = entry.file_name().to_str().unwrap();
            println!("packaging from initfs: {}", name);
            tar.append_file(name, &mut File::open(entry.path())?)?;
        }
    }

    for entry in WalkDir::new("userspace/target/wasm32-unknown-unknown/release/")
                        .max_depth(1)
                         .into_iter()
                         .filter_map(|e| e.ok()) {
        if is_wasm(&entry) {
            assert!(entry.file_type().is_file());
            let name = entry.file_name().to_str().unwrap();
            println!("packaging: {}", name);
            tar.append_file(name, &mut File::open(entry.path())?)?;
        }
    }

    Ok(())
}