Function rayon::par_iter::fold::fold

pub fn fold<U, BASE, IDENTITY, FOLD_OP>(base: BASE,
                                        identity: IDENTITY,
                                        fold_op: FOLD_OP)
                                        -> Fold<BASE, IDENTITY, FOLD_OP> where BASE: ParallelIterator,
        FOLD_OP: Fn(U, BASE::Item) -> U + Sync,
        IDENTITY: Fn() -> U + Sync,
        U: Send