pub fn pop_back(&mut self) -> Option<T> {
        if self.is_empty() {
            None
        } else {
            self.head = self.wrap_sub(self.head, 1);
            let head = self.head;
            unsafe { Some(self.buffer_read(head)) }
        }
    }
Removes an element from anywhere in the `VecDeque` and returns it, replacing it with the
last
benchmarks/haystacks/code/rust-library.rs