kotlin flow retrying forever (callbacks)

kotlin-flow-retrying-forever-callbacks.kt

// kinds of callbacks
channelFlow {
    do.something(object: SomethingListher {
        override fun onSomething(something: Something?) {
            send(something)
        }
    })
}.mapNotNull {
    if (it == null) {
        throw Exception()
    }
    it
}.retryWhen { _, _ ->
    delay(5 * 1000L)
    true
}.collect { // or .single()
    // finally do something meaningful
}