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: asciicast.rs
    path of file: ./repos/asciinema/src
    
    the code of the file until where you have to start completion: mod util;
mod v1;
mod v2;
use crate::tty;
use anyhow::{anyhow, Result};
use std::collections::HashMap;
use std::fs;
use std::io::{self, BufRead};
use std::path::Path;
pub use v2::Writer;

pub struct Asciicast<'a> {
    pub header: Header,
    pub events: Box<dyn Iterator<Item = Result<Event>> + 'a>,
}

pub struct Header {
    pub version: u8,
    pub cols: u16,
    pub rows: u16,
    pub timestamp: Option<u64>,
    pub idle_time_limit: Option<f64>,
    pub command: Option<String>,
    pub title: Option<String>,
    pub env: Option<HashMap<String, String>>,
    pub theme: Option<tty::Theme>,
}

pub struct Event {
    pub time: u64,
    pub data: EventData,
}

pub enum EventData {
    Output(String),
    Input(String),
    Resize(u16, u16),
    Marker(String),
    Other(char, String),
}

pub fn open_from_path<S: AsRef<Path>>(path: S) -> Result<Asciicast<'static>> {
    fs::File::open(path)
        .map(io::BufReader::new)
        .map_err(|e| anyhow!(e))
        .and_then(open)
        .map_err(|e| anyhow!("can't open asciicast file: {e}"))
}

pub fn open<'a, R: BufRead + 'a>(reader: R) -> Result<Asciicast<'a>> {
    let mut lines = reader.lines();
    let first_line = lines.next().ok_or(anyhow!("empty file"))??;

    if let Ok(parser) = v2::open(&first_line) {
        Ok(parser.parse(lines))
    } else {
        let json = std::iter:
    
    fn writer() {
        let mut data = Vec::new();

        {
            let mut fw = Writer::new(&mut data, 0);

            let header = Header {
                version: 2,
                cols: 80,
                rows: 24,
                timestamp: None,
                idle_time_limit: None,
                command: None,
                title: None,
                env: Default::default(),
                theme: None,
            };

            fw.write_header(&header).unwrap();

            fw.write_event(&Event::output(1000001, "hello\r\n".to_owned()))
                .unwrap();
        }

        {
            let mut fw = Writer::new(&mut data, 1000001);

            fw.write_event(&Event::output(1000001, "world".to_owned()))
                .unwrap();

            fw.write_event(&Event::input(2000002, " ".to_owned()))
                .unwrap();

            fw.write_event(&Event::resize(3000003, (100, 40))).unwrap();

            fw.write_event(&Event::output(4000004, "żółć".to_owned()))
                .unwrap();
        }

        let lines = parse(data);

        assert_eq!(lines[0]["version"], 2);
        assert_eq!(lines[0]["width"], 80);
        assert_eq!(lines[0]["height"], 24);
        assert!(lines[0]["timestamp"].is_null());
        assert_eq!(lines[1][0], 1.000001);
        assert_eq!(lines[1][1], "o");
        assert_eq!(lines[1][2], "hello\r\n");
        assert_eq!(lines[2][0], 2.000002);
        assert_eq!(lines[2][1], "o");
        assert_eq!(lines[2][2], "world");
        assert_eq!(lines[3][0], 3.000003);
        assert_eq!(lines[3][1], "i");
        assert_eq!(lines[3][2], " ");
        assert_eq!(lines[4][0], 4.000004);
        assert_eq!(lines[4][1], "r");
        assert_eq!(lines[4][2], "100x40");
        assert_eq!(lines[5][0], 5.000005);
        assert_eq!(lines[5][1], "o");
        assert_eq!(lines[5][2], "żółć");
    }