Sends the elements of the stream to the given IActorRef that sends back back-pressure signal. First element is always onInitMessage, then stream is waiting for acknowledgement message ackMessage from the given actor which means that it is ready to process elements.It also requires ackMessage message after each stream element to make backpressure work. If the target actor terminates the stream will be canceled. When the stream is completed successfully the given onCompleteMessage will be sent to the destination actor. When the stream is completed with failure - result of onFailureMessage function will be sent to the destination actor.

public static Sink<TIn, NotUsed> ActorRefWithAck<TIn>(
	IActorRef actorRef,
	Object onInitMessage,
	Object ackMessage,
	Object onCompleteMessage,
	Func<Exception, Object> onFailureMessage = null
)

static member ActorRefWithAck : 
        actorRef : IActorRef * 
        onInitMessage : Object * 
        ackMessage : Object * 
        onCompleteMessage : Object * 
        ?onFailureMessage : Func<Exception, Object> 
(* Defaults:
        let _onFailureMessage = defaultArg onFailureMessage null
*)
-> Sink<'TIn, NotUsed>