You can also have a look at ConflatedBroadcastChannel: https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.experimental.channels/-conflated-broadcast-channel/index.html

So just to close the loop, this didn’t offer exactly what I was looking for out of the box, but a small extension method got me there:

fun <T> ConflatedBroadcastChannel<T>.valueOrWait(): T {
    while (true) {
        val result = this.valueOrNull
        if (result != null) {
            return result
        }
    }
}

looks similar to an extension function i use:

suspend fun <T> BroadcastChannel<T>.waitUntil(value: T): T {
    consume {
        for (element in this)
            if (element == value)
                return value
    }

    throw CancellationException("channel closed before item received")
}

But

consume

will pop the element out of the queue, right?

it's a broadcast channel, there's no problem with popping it out of (your subscription). It wont effect anyone else getting elements.

Both good points, I'll take another look at it. Thanks!