let mut reader = BufReader::with_capacity(5, ErrAfterFirstSeekReader { first_seek: true });
assert_eq!(reader.fill_buf().ok(), Some(&[0, 0, 0, 0, 0][..]));
let mut reader = BufReader::with_capacity(5, ErrAfterFirstSeekReader { first_seek: true });
assert_eq!(reader.fill_buf().ok(), Some(&[0, 0, 0, 0, 0][..]));