pub fn drain_sorted(&mut self) -> DrainSorted<'_, T> {
        DrainSorted { inner: self }
    }
Returns the greatest item in the binary heap, or `None` if it is empty.

# Examples

Basic usage:

```
use std::collections::BinaryHeap;
let mut heap = BinaryHeap::new();
assert_eq!(heap.peek(), None);

heap.push(1);
heap.push(5);
heap.push(2);
benchmarks/haystacks/code/rust-library.rs