Function std::iter::iterateUnstable

pub fn iterate<T, F>(seed: T, f: F) -> Unfold<(F, Option<T>, bool), fn(&mut (F, Option<T>, bool)) -> Option<T>> where T: Clone, F: FnMut(T), <F as FnMut(T)>::Output == T

Create a new iterator that produces an infinite sequence of repeated applications of the given function f.