use std::io::IoSlice;
use std::io::prelude::*;
use std::fs;
use std::fs::OpenOptions;

fn main() -> std::io::Result<()> {
    let mut data1 = [1; 8];
    let mut data2 = [15; 8];
    let io_slice1 = IoSlice::new(&mut data1);
    let io_slice2 = IoSlice::new(&mut data2);

    let mut f = OpenOptions::new().write(true).read(true).create(true).open("foo.txt").unwrap();
    f.write_vectored(&[io_slice1, io_slice2])?;
    f.flush()?;
    let mut buffer = [0; 16];
    let n = f.read(&mut buffer[..])?;
    println!("The lens: {:?}", n);
    println!("The bytes: {:?}", &buffer[..n]);
    println!("{:?}", fs::read_to_string("foo.txt")?.as_bytes());
    Ok(())
}