leftover
leftover is a BufRead adapter that keeps partial data available across buffer
boundaries.
use BufReader;
use LeftoverReader;
let input = with_capacity;
let mut reader = new;
// Copy the incomplete line into the leftover before reading more.
reader.fill_view.unwrap.accumulate;
let view = reader.fill_view.unwrap;
assert_eq!;
assert_eq!;
// Take the saved prefix together with three bytes from the current chunk.
assert_eq!;