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kotlinlang

I'm debating if I should abandon Google Guava which I primarily only use for its Immutable Collections.   While I didn't benchmark, I am getting the sense the performance benefit has been marginalized over the years and it's not worth the dependency bloat. However, I would like to have 100% immutability and not just unmodifiable wrappers. I don't know how I feel about persistent immutable collections that have "modification" methods that return new collections, and I noticed Kotlin is coming up with its own. Is there a performance benefit to this library or immutable collections anymore? Or is it more for safety? <https://github.com/Kotlin/kotlinx.collections.immutable>