Feature Request: `count_by` under `no_std`

[fxdmhtt]

Thanks to the existence of the hashbrown crate, it is possible to provide no_std support for HashMap—provided that alloc is enabled.

The code itself remains unchanged; only the import statements need to be modified.

use core::hash::Hash;

use hashbrown::HashMap;

pub trait Counts: Iterator {
    fn counts(self) -> HashMap<Self::Item, usize>
    where
        Self: Sized,
        Self::Item: Eq + Hash,
    {
        let mut counts = HashMap::new();
        self.for_each(|item| *counts.entry(item).or_default() += 1);
        counts
    }
}

impl<I: Iterator> Counts for I {}

Would you consider adding this support? Doing so would broaden the applicability of the APIs related to HashMap and HashSet.