A really simple stopwatch for Kotlin

Stopwatch.kt

object Stopwatch {
    inline fun elapse(callback: () -> Unit): Long {
        var start = System.currentTimeMillis()
        callback()
        return System.currentTimeMillis() - start
    }

    inline fun elapseNano(callback: () -> Unit): Long {
        var start = System.nanoTime()
        callback()
        return System.nanoTime() - start
    }
}

now we have
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.system/
measureXYZ methods