My usecase is to build a lazy cache with a ConflatedBroadcastChannel where when a subscriber is suspending on

receive()

, some code that will send stuff into the channel is executed

You could wrap your channel to do something on receive

val delegateChannel = ConflatedBroadcastChannel<Int>()
suspend fun ConflatedBroadcastChannel<Int>.populate() {
    send(10)
}

val subscription = delegateChannel.openSubscription()
val channel = object : ReceiveChannel<Int> by subscription {
    private val populated = AtomicBoolean(false)

    override suspend fun receive() = this.run {
        populate()
        subscription.receive()
    }

    private suspend fun populate() {
        if (!populated.get()) {
            delegateChannel.populate()
            populated.set(true)
        }
    }
}