unsafe fn rotate_right_inner(&mut self, k: usize) {
        debug_assert!(k * 2 <= self.len());
        self.head = self.wrap_sub(self.head, k);
        self.tail = self.wrap_sub(self.tail, k);
        unsafe {
            self.wrap_copy(self.tail, self.head, k);
        }
    }
Binary searches this sorted `VecDeque` with a comparator function.

The comparator function should implement an order consistent
with the sort order of the underlying `VecDeque`, returning an
order code that indicates whether its argument is `Less`,
`Equal` or `Greater` than the desired target.
benchmarks/haystacks/code/rust-library.rs