Turns an iterator of AsRef<[u8]> into a reader implements std::io::Read.
let chunks: &[&[u8]] = &[
b"", b"ab", b"", b"c", b"defg", b"", b"hij", b"klmnop", b"qrstuvw", b"", b"", b"xyz",
b"", b"",
];
let mut reader = Reader::new(chunks.into_iter());
let mut result = String::new();
let total_length = reader.read_to_string(&mut result).unwrap();
assert_eq!(result, "abcdefghijklmnopqrstuvwxyz");
assert_eq!(total_length, 26);