why there's no difference between the output of these two? Im trying to understand when to use

k()

and when not to use it.

val fruits = listOf("apple", "aabb", "ab", "apricot", "banana", "blueberry", "cherry", "coconut")
val evenFruits = fruits.k()
            .fold(listOf<String>()) { acc, e -> if (e.length % 2 == 0) acc + e else acc }

val evenFruits2 = fruits
           .fold(listOf<String>()) { acc, e -> if (e.length % 2 == 0) acc + e else acc }

println(evenFruits) 
println(evenFruits2)

what in hat is

.k()

supposed to be?