does kotlin uses `experimental` features in its in...

# announcements

[amadeu01]

does kotlin uses experimental features in its internal's implementations? I was checking

@Suppress("NOTHING_TO_INLINE")
internal class CoroutineScheduler(
    private val corePoolSize: Int,
    private val maxPoolSize: Int,
    private val idleWorkerKeepAliveNs: Long = IDLE_WORKER_KEEP_ALIVE_NS,
    private val schedulerName: String = DEFAULT_SCHEDULER_NAME
) : Executor, Closeable {
    init {
        require(corePoolSize >= MIN_SUPPORTED_POOL_SIZE) {
            "Core pool size $corePoolSize should be at least $MIN_SUPPORTED_POOL_SIZE"
        }
        require(maxPoolSize >= corePoolSize) {
            "Max pool size $maxPoolSize should be greater than or equals to core pool size $corePoolSize"
        }

@kotlin.internal.InlineOnly
public inline fun require(value: Boolean, lazyMessage: () -> Any): Unit {
    contract {
        returns() implies value
    }

@ContractsDsl
@ExperimentalContracts
@InlineOnly
@SinceKotlin("1.3")
@Suppress("UNUSED_PARAMETER")
public inline fun contract(builder: ContractBuilder.() -> Unit) { }