merklol

sealed class FList<out A> {
    object Empty : FList<Nothing>()

    data class Node<out A>(val head: A, val tail: FList<A>) : FList<A>() {
        override fun toString() =
            foldLeft("[", { acc: String, initial: A -> "$acc$initial, " }).dropLast(2) + "]"
    }

    companion object {
        fun <A> of(element: A): FList<A> = Node(element, Empty)

merklol

class StopWatch {
    private val disposableBag = CompositeDisposable()
    var onTick: (String) -> Unit = {}
    var elapsedTime: Long = 0

    companion object {
        const val INITIAL_VALUE = "00:00:00"
    }

    fun start() {