Equivalent to peek followed by toss.
The data returned is invalidated by the next call to take, peek,
fill, and functions with those prefixes.
pub fn take(r: *Reader, n: usize) Error![]u8
pub fn take(r: *Reader, n: usize) Error![]u8 {
const result = try r.peek(n);
r.toss(n);
return result;
}