How to window the fixed-size buffered items in Channel?

When using Channel with capacity > 0, like Channel(3) I want to keep the buffered item inside the channel as fresh as possible, The use-case is like following:

fun bufferChannel() {
        val channel = Channel<Int>(3)
        scope.launch {
            launch {
                (1..10).forEach {
                    println("send $it")
                    channel.send(it)
                }
                channel.close()
                println("done send")
            }

            launch {
                delay(2000)
                println("recv start consume")
                channel.consumeEach {
                    println("recv $it")
                }
                println("done recv")
            }
        }
    }

I’m looking for a way to let the receiver receives the latest items, e.g.

recv 8
recv 9
recv 10

Is there a way to drop the oldest item in the channel when offer new items to the channel?

[diousk]

@elizarov It’s designed for the chat room of live streaming. Sometimes there’s a large number of messages sent from websocket, and we’d like the viewers to see the new messages as fresh as possible. Due to the back pressure, we need to control the message buffer size and drop some messages and here we choose to drop the oldest ones.

[elizarov]

Thanks. I know that you can do it in Rx and we are also looking at whether we need to add this kind of a feature to Kotlin flow. For that, we need to know the details. My question if where do you find the need to use it. What is the domain you are working with and what kind of events are you working with?