Kotlin Coroutine Understanding

CoroutineUnderstanding.kt

/**
 * You can edit, run, and share this code. 
 * play.kotlinlang.org 
 */
import kotlinx.coroutines.*
import kotlinx.coroutines.flow.*
import kotlin.system.*

fun test1() {
    var time = 0L
    runBlocking {
        time = measureTimeMillis {
            val deferred1 = async { 
                delay(1000)
                println("1") 
            }
        	println("2")
        	deferred1.await()
        }
    }
    println("last $time ms")
}

fun test2() {
    var parentTime = 0L
    var time = 0L
    val parentJob = SupervisorJob()
    val parentScope = CoroutineScope(parentJob)
    parentTime = measureTimeMillis {
        runBlocking {
            val job = parentScope.launch {
                time = measureTimeMillis {
                    channelFlow {
                        launch {
                            delay(1000)
                            println("1")
                            1
                        }
                        flow {
                            delay(800)
                            emit(2)
                        }.collect {
                            println("2")
                            send(it)
                        }
                    }
                    .flowOn(Dispatchers.IO)
                    .collect {
                        println(it)
                    }
                }   
            }
            delay(500)
            job.cancel()
            println("inside scope $time ms")            
        }
    }
    println("last $parentTime ms")
}

fun main() {
    test2()
}