AnonymousClassCapture.kt

import kotlinx.coroutines.CoroutineName
import kotlinx.coroutines.delay
import kotlinx.coroutines.runBlocking
import kotlinx.coroutines.withContext
import kotlin.random.Random

suspend fun build(): () -> Unit {
    val number = Random(239).nextInt()
    return withContext<() -> Unit>(CoroutineName("produce value")) {
        delay(1)
        object : () -> Unit() {
            override fun invoke() {
                if (number != 0) {
                    Thread.sleep(1)
                }
            }
        }
    }
}

fun main() {
    val value = runBlocking { build() }
    val wrapper = value.javaClass.getDeclaredField("this$0")
    val delegate = wrapper.get(value)
    println(delegate.javaClass.declaredFields.joinToString(
            prefix = "{\n   ", separator = "\n   ", postfix = "\n}\n"
    ) {
        "${it.name}: ${it.type.name}"
    })
    val coroutine = delegate.javaClass.getDeclaredField("L\$0")
    println("found coroutine: ${coroutine.get(delegate).javaClass.name}")
    value()
}