Mastering High Performance with Kotlin

The async function

The async function creates a new coroutine and returns an instance of the Deferred type:

public actual fun <T> async(    context: CoroutineContext = DefaultDispatcher,    start: CoroutineStart = CoroutineStart.DEFAULT,    parent: Job? = null,    block: suspend CoroutineScope.() -> T): Deferred<T> {    val newContext = newCoroutineContext(context, parent)    val coroutine = if (start.isLazy)        LazyDeferredCoroutine(newContext, block) else        DeferredCoroutine<T>(newContext, active = true)    coroutine.initParentJob(newContext[Job])    start(block, coroutine, coroutine)    return coroutine}

Deferred is an interface that represents a future result of a coroutine execution:

public actual interface Deferred<out T> : Job {   public actual val isCompletedExceptionally: ...