measureTimeMillis.kt

@OptIn(ExperimentalContracts::class)
fun <T: () -> R, R> T.measureTimeMillis(test: Boolean = true, onMeasure: (Long) -> Unit): R {
        contract {
                callsInPlace(this@measureTimeMillis, InvocationKind.EXACTLY_ONCE)
        }
        if (!test) return this()

        val start = System.currentTimeMillis()
        val res = this()
        onMeasure(System.currentTimeMillis() - start)
        return res
}