toMutableSet
Returns a new MutableSet containing all distinct elements from the given sequence.
fun <T> Sequence<T>.toMutableSet(): MutableSet<T>(source)
fun main() {
val numbers = sequenceOf(1, 2, 3, 2, 4)
val mutableSet = numbers.toMutableSet() // {1, 2, 3, 4}
mutableSet.add(5) // add another element
println(mutableSet) // prints: [1, 2, 3, 4, 5]
}