Differences from linked-hash-map? about indexmap

[bluss]

OrderMap's iteration is probably a mountain faster. About lookups we don't claim to be faster than HashMap in general. It benches a bit faster for smaller cases, but we also know that OrderMap has a greater indirection / cache hit cost to lookups.

Very important to note: OrderMap's guarantee is an order that is consistent, not dependent on key hashes, and depends on the sequence of inserts and removals. It does not keep strict insertion order like linked hashmap. It's also unsuitable to use as an LRU cache, and it can not "pop front" and so on.

I recommend OrderMap when it's a good fit, but it's quite different from the linked hashmap.

[dtolnay]

Thanks for the explanation and for weighing in on our yaml-rust discussion.