flatten

fun <K, V> Flow<Map<K, Flow<V?>>>.flatten(throttle: Duration = 200.milliseconds): Flow<Map<K, V?>>

@JvmName(name = "flattenList")

inline fun <V> Flow<List<Flow<V?>>>.flatten(throttle: Duration = 200.milliseconds): Flow<List<V>>

A change of the outer flow results in new collect of the inner flows. Because this is an expensive operation, the outer flow is throttled by default.