Function fractal_analysis::map_sampler

pub fn map_sampler<'a, H: 'a, Smp, Key: 'a, Set>(
    set: Set, 
    get_key_from_sample: H
) -> impl Iterator<Item = Key> + 'a where
    H: Fn(Smp) -> Key,
    Key: PrimInt,
    Set: IntoIterator<Item = Smp> + 'a,