Premature evicting entries in HashCache

[feymartynov]

The following example often panics proving that HashCache may evict entries even when capacity is not yet fully occupated.

const CAPACITY: usize = 64;
let hc = scc::HashCache::with_capacity(CAPACITY, CAPACITY);

for i in 0..CAPACITY {
    let k = format!("key{i}");

    match hc.put(k, i).unwrap() {
        None => (),
        Some((k, _)) => panic!("Evicted {k}"),
    }
}

Is this a bug or normal behavior? If it's normal, I think it should be documented.

[wvwwvwwv]

Hi!

It’s unfortunately intended. HashCache is basically the same with HashMap except that it evicts an entry if the bucket is full instead of allocating backup linked list storage, even when there are free slots in other buckets. I’ll add this to the document!

[wvwwvwwv]

Updated the doc!