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: create_train_dataset.rs
    path of file: ./repos/whichlang/src/bin
    
    the code of the file until where you have to start completion: use std::io;
use std::io::BufRead;
use std::io::BufReader;
use std::io::BufWriter;
use std::io::Write;

use whichlang::emit_tokens;
use whichlang::DIMENSION;

fn main() -> io::Result<()> {
    let language_codes = whichlang::LANGUAGES
        .iter()
        .map(|lang| lang.three_letter_code())
        .collect::<Vec<&str>>();
    let mut line = String::new();
    let mut features: Vec<usize> = vec![0; whichlang::DIMENSION];
    let stdin = io::stdin();
    let mut stdinlocked = BufReader::new(stdin.lock());
    let stdout = io::stdout();
    let mut stdoutlock = BufWriter::new(stdout.lock());
    write!(&mut stdoutlock, "id,label")?;
    for i in 0..whichlang::DIMENSION {
        write!(&mut stdoutlock, ",feature{i}")?;
    }
    writeln!(&mut stdoutlock)?;
    loop {
        line.clear();
        if stdinlocked.read_line(&mut line)? == 0 {
            break;
        }
        let trimmed_line = line.trim_end().trim_matches('\\');
        features.fill(0);
        let id_label_sentence: Vec<&str> = trimmed_line.splitn(3, "\t").collect();
        if !language_codes.contains(&id_label_sentence[1]) {
            continue;
        }
        let sentence: &str = id_label_sentence[2];
        emit_tokens(sentence, |token| {
            features[token.to_hash() as usize % DIMENSION] += 1;
        });
        write!(
            &mut stdoutlock,
            "{},{}",
            id_label_sentence[0], id_label_sentence[1]
        )?;
        for i in 0..which
    
fn main() -> io::Result<()> {
    let language_codes = whichlang::LANGUAGES
        .iter()
        .map(|lang| lang.three_letter_code())
        .collect::<Vec<&str>>();
    let mut line = String::new();
    let mut features: Vec<usize> = vec![0; whichlang::DIMENSION];
    let stdin = io::stdin();
    let mut stdinlocked = BufReader::new(stdin.lock());
    let stdout = io::stdout();
    let mut stdoutlock = BufWriter::new(stdout.lock());
    write!(&mut stdoutlock, "id,label")?;
    for i in 0..whichlang::DIMENSION {
        write!(&mut stdoutlock, ",feature{i}")?;
    }
    writeln!(&mut stdoutlock)?;
    loop {
        line.clear();
        if stdinlocked.read_line(&mut line)? == 0 {
            break;
        }
        let trimmed_line = line.trim_end().trim_matches('\\');
        features.fill(0);
        let id_label_sentence: Vec<&str> = trimmed_line.splitn(3, "\t").collect();
        if !language_codes.contains(&id_label_sentence[1]) {
            continue;
        }
        let sentence: &str = id_label_sentence[2];
        emit_tokens(sentence, |token| {
            features[token.to_hash() as usize % DIMENSION] += 1;
        });
        write!(
            &mut stdoutlock,
            "{},{}",
            id_label_sentence[0], id_label_sentence[1]
        )?;
        for i in 0..whichlang::DIMENSION {
            let feature = features[i];
            write!(&mut stdoutlock, ",{feature}")?;
        }
        write!(&mut stdoutlock, "\n")?;
        line.clear();
    }
    Ok(())
}