pub(super) fn fast_collect<I, T>(pi: I) -> Either<Vec<T>, LinkedList<Vec<T>>> ⓘwhere
    I: IntoParallelIterator<Item = T>,
    T: Send,pub(super) fn fast_collect<I, T>(pi: I) -> Either<Vec<T>, LinkedList<Vec<T>>> ⓘwhere
    I: IntoParallelIterator<Item = T>,
    T: Send,