TimingLogger.kt

class TimingLogger(
    private val step: Long,
    private val timeUnit: TimeUnit,
    private val template: String,
    private val counterScaler: Long = 1,
    private val log: (String) -> Unit
) {
    private var tickCounter: Long = 0L
    private var timeMark = System.nanoTime()

    fun tick() {
        tickCounter++
        if ((tickCounter % step) == 0L) {

            val t = timeUnit.convert(System.nanoTime() - timeMark, NANOSECONDS)
            val n = tickCounter / counterScaler

            timeMark = System.nanoTime()
            log(template.format(n, t))
        }
    }
}