suspend fun main() {
    log("main -> start")
    val producer = Coroutine.create<Unit, Int>(Dispatcher()) {
        200.also { log("send", it) }
    }

    val consumer = Coroutine.create<Int, Unit>(Dispatcher()) { param: Int ->
        log("start", param)
    }

    while (producer.isActive && consumer.isActive) {
        val result = producer.resume(Unit)
        log("main -> middle")
        consumer.resume(result)
    }
    log("main -> end")
}

输出：

20:44:44:775 [main] main -> start
20:44:44:853 [Thread-0] send 200
20:44:44:853 [Thread-0] main -> middle
20:44:44:853 [Thread-1] start 200
20:44:44:853 [Thread-1] main -> end

非对称协程，不是在线程A挂起，在线程B执行完返回线程A；那么不是在A挂起点返回后的代码都应该执行在A的线程，现在的运行结果确实在B的线程继续执行，并没有切换回来