pub fn difference<'a>(&'a self, other: &'a BTreeSet<T>) -> Difference<'a, T>
    where
        T: Ord,
    {
        let (self_min, self_max) =
            if let (Some(self_min), Some(self_max)) = (self.first(), self.last()) {
                (self_min, self_max)
            } else {
                return Difference { inner: DifferenceInner::Iterate(self.iter()) };
            };
        let (other_min, other_max) =
            if let (Some(other_min), Some(other_max)) = (other.first(), other.last()) {
                (other_min, other_max)
            } else {
                return Difference { inner: DifferenceInner::Iterate(self.iter()) };
            };
        Difference {
            inner: match (self_min.cmp(other_max), self_max.cmp(other_min)) {
                (Greater, _) | (_, Less) => DifferenceInner::Iterate(self.iter()),
                (Equal, _) => {
                    let mut self_iter = self.iter();
                    self_iter.next();
                    DifferenceInner::Iterate(self_iter)
                }
                (_, Equal) => {
                    let mut self_iter = self.iter();
                    self_iter.next_back();
                    DifferenceInner::Iterate(self_iter)
                }
                _ if self.len() <= other.len() / ITER_PERFORMANCE_TIPPING_SIZE_DIFF => {
                    DifferenceInner::Search { self_iter: self.iter(), other_set: other }
                }
                _ => DifferenceInner::Stitch {
                    self_iter: self.iter(),
                    other_iter: other.iter().peekable(),
                },
            },
        }
    }
Visits the values representing the intersection,
i.e., the values that are both in `self` and `other`,
in ascending order.

# Examples

```
use std::collections::BTreeSet;

let mut a = BTreeSet::new();
a.insert(1);
a.insert(2);

let
benchmarks/haystacks/code/rust-library.rs