internal sealed interface Command
private data class Connect(...) : Command
private data class Subscribe(
...
) : Command

private data class Publish(...) : Command
private data class ClientConnected(...) : Command
private data class ClientDisconnected(...) : Command
...
//non-exhaustive when here
    when (val cmd : Command = receive()) {
                is Connect -> { true}
                is Subscribe -> {true }
                is Publish -> {true}
                is ClientConnected -> {true}
                is ClientDisconnected -> {true}
            }

receive