getTimeNanos

external fun getTimeNanos(): Long(source)

import kotlin.system.getTimeNanos

fun main() {
    val start = getTimeNanos()
    // Simulate some work
    Thread.sleep(500)
    val end = getTimeNanos()

    val elapsedMillis = (end - start) / 1_000_000
    println("Elapsed time: $elapsedMillis ms")
}