use std::io::prelude::*;
use std::io::Cursor;
use std::io::{SeekFrom};

fn main() {
    let mut buf = Cursor::new(vec![0; 15]);

    let bytes_read = buf.write(&[1, 2, 3, 4, 5]).unwrap();
    buf.flush().unwrap();

    assert_eq!(bytes_read, 5);

    let mut buf_read = vec![0; 5];

    buf.seek(SeekFrom::Start(0)).unwrap();
    buf.read(&mut buf_read).unwrap();

    assert_eq!(&buf_read, &[1, 2, 3, 4, 5]);
}