pub fn as_slices(&self) -> (&[T], &[T]) {
        unsafe {
            let buf = self.buffer_as_slice();
            RingSlices::ring_slices(buf, self.head, self.tail)
        }
    }
Creates an iterator that covers the specified range in the `VecDeque`.

# Panics

Panics if the starting point is greater than the end point or if
the end point is greater than the length of the vector.

# Examples

```
use std::collections::VecDeque;
benchmarks/haystacks/code/rust-library.rs