fn clone(&self) -> Self {
        match *self {
            Borrowed(b) => Borrowed(b),
            Owned(ref o) => {
                let b: &B = o.borrow();
                Owned(b.to_owned())
            }
        }
    }
Extracts the owned data.

Clones the data if it is not already owned.
benchmarks/haystacks/code/rust-library.rs