private sealed interface FlowMessage<out T>
private data class FlowValue<T>(val value: T): FlowMessage<T>
private object EndOfFlow: FlowMessage<Nothing>

fun <T> Flow<T>.shareCompletableIn(
    scope: CoroutineScope,
    started: SharingStarted,
    replay: Int = 0
) = this
    .map<T, FlowMessage<T>> { FlowValue(it) }
    .onCompletion { emit(EndOfFlow) }
    .shareIn(
        scope = scope,
        started = started,
        replay = replay
    )
    .takeWhile { it !is EndOfFlow }
    .filterIsInstance<FlowValue<T>>()
    .map { it.value }

replay

replay+1

EnfOfFlow