How do I consume rayon Fold that returns HashMap<usize,String>

I am trying to fold a rayon iterator into a HashMap<usize,String> but the only thing i can get is a Fold struct which i can make of no use

You want ParallelIterator::collect to create the HashMap

I tried that but seems it is not implemented for HashMap<usize,String>

Can you show us your code? Because this works:

fn main() {
    let hash_map: HashMap<usize, String> = vec![(0, "test".to_string())].into_par_iter().collect();

Collect should be the easiest, but for general fold do see its docs for an explanation how and why it is different than Iterator::fold.