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.

Declaration

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

Parameters

Type	Name	Description
IActorRef	actorRef	TBD
object	onInitMessage	TBD
object	ackMessage	TBD
object	onCompleteMessage	TBD
Func<Exception, object>	onFailureMessage	TBD

Returns

Type	Description
Sink<TIn, NotUsed>	TBD

Type Parameters

Name	Description
TIn	TBD

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ActorRef<TIn>(IActorRef, object)

Sends the elements of the stream to the given IActorRef. 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 a Status.Failure message will be sent to the destination actor.

It will request at most MaxInputBufferSize number of elements from upstream, but there is no back-pressure signal from the destination actor, i.e. if the actor is not consuming the messages fast enough the mailbox of the actor will grow. For potentially slow consumer actors it is recommended to use a bounded mailbox with zero PushTimeOut or use a rate limiting stage in front of this Sink<TIn, TMat>.

Declaration

[Obsolete("Use overload accepting both on complete and on failure message")]
public static Sink<TIn, NotUsed> ActorRef<TIn>(IActorRef actorRef, object onCompleteMessage)

Parameters

Type	Name	Description
IActorRef	actorRef	TBD
object	onCompleteMessage	TBD

Returns

Type	Description
Sink<TIn, NotUsed>	TBD

Type Parameters

Name	Description
TIn	TBD

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ActorRef<TIn>(IActorRef, object, Func<Exception, object>)

INTERNAL API

Sends the elements of the stream to the given IActorRef. 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 the onFailureMessage will be invoked and its result will be sent to the destination actor.

Declaration

public static Sink<TIn, NotUsed> ActorRef<TIn>(IActorRef actorRef, object onCompleteMessage, Func<Exception, object> onFailureMessage)

Parameters

Type	Name	Description
IActorRef	actorRef	TBD
object	onCompleteMessage	TBD
Func<Exception, object>	onFailureMessage	TBD

Returns

Type	Description
Sink<TIn, NotUsed>

Type Parameters

Name	Description
TIn	TBD

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ActorSubscriber<TIn>(Props)

Creates a Sink<TIn, TMat> that is materialized to an IActorRef which points to an Actor created according to the passed in Props. Actor created by the props should be Akka.Streams.Implementation.ActorSubscriberSink<TIn>.

Declaration

public static Sink<TIn, IActorRef> ActorSubscriber<TIn>(Props props)

Parameters

Type	Name	Description
Props	props	TBD

Returns

Type	Description
Sink<TIn, IActorRef>	TBD

Type Parameters

Name	Description
TIn	TBD

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AggregateAsync<TIn, TOut>(TOut, Func<TOut, TIn, Task<TOut>>)

A Sink<TIn, TMat> that will invoke the given asynchronous function for every received element, giving it its previous output (or the given zero value) and the element as input. The returned Task will be completed with value of the final function evaluation when the input stream ends, or completed with "Failure" if there is a failure signaled in the stream.

Aggregate<TIn, TOut>(TOut, Func<TOut, TIn, TOut>)

Declaration

public static Sink<TIn, Task<TOut>> AggregateAsync<TIn, TOut>(TOut zero, Func<TOut, TIn, Task<TOut>> aggregate)

Parameters

Type	Name	Description
TOut	zero	TBD
Func<TOut, TIn, Task<TOut>>	aggregate	TBD

Returns

Type	Description
Sink<TIn, Task<TOut>>	TBD

Type Parameters

Name	Description
TIn	TBD
TOut	TBD

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Aggregate<TIn, TOut>(TOut, Func<TOut, TIn, TOut>)

A Sink<TIn, TMat> that will invoke the given aggregate function for every received element, giving it its previous output (or the given zero value) and the element as input. The returned Task will be completed with value of the final function evaluation when the input stream ends, or completed with the streams exception if there is a failure signaled in the stream. AggregateAsync<TIn, TOut>(TOut, Func<TOut, TIn, Task<TOut>>)

Declaration

public static Sink<TIn, Task<TOut>> Aggregate<TIn, TOut>(TOut zero, Func<TOut, TIn, TOut> aggregate)

Parameters

Type	Name	Description
TOut	zero	TBD
Func<TOut, TIn, TOut>	aggregate	TBD

Returns

Type	Description
Sink<TIn, Task<TOut>>	TBD

Type Parameters

Name	Description
TIn	TBD
TOut	TBD

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AsObservable<T>()

A Sink<TIn, TMat> that materializes into a IObservable<T>. It supports multiple subscribers. Since observables have no notion of backpressure, it will push incoming elements as fast as possible, potentially risking process overrun.

Declaration

public static Sink<T, IObservable<T>> AsObservable<T>()

Returns

Type	Description
Sink<T, IObservable<T>>

Type Parameters

Name	Description
T

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AsPublisher<TIn>(bool)

A Sink<TIn, TMat> that materializes into a Reactive.Streams.IPublisher<T>. If fanout is true, the materialized Reactive.Streams.IPublisher<T> will support multiple Reactive.Streams.ISubscriber<T>`s and the size of the MaxInputBufferSize configured for this stage becomes the maximum number of elements that the fastest Reactive.Streams.ISubscriber<T> can be ahead of the slowest one before slowing the processing down due to back pressure.

If fanout is false then the materialized Reactive.Streams.IPublisher<T> will only support a single Reactive.Streams.ISubscriber<T> and reject any additional Reactive.Streams.ISubscriber<T>`s.

Declaration

public static Sink<TIn, IPublisher<TIn>> AsPublisher<TIn>(bool fanout)

Parameters

Type	Name	Description
bool	fanout	TBD

Returns

Type	Description
Sink<TIn, IPublisher<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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Cancelled<TIn>()

A Sink<TIn, TMat> that immediately cancels its upstream after materialization.

Declaration

public static Sink<TIn, NotUsed> Cancelled<TIn>()

Returns

Type	Description
Sink<TIn, NotUsed>	TBD

Type Parameters

Name	Description
TIn	TBD

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ChannelReader<T>(int, bool, BoundedChannelFullMode)

Declaration

public static Sink<T, ChannelReader<T>> ChannelReader<T>(int bufferSize, bool singleReader, BoundedChannelFullMode fullMode = BoundedChannelFullMode.Wait)

Parameters

Type	Name	Description
int	bufferSize
bool	singleReader
BoundedChannelFullMode	fullMode

Returns

Type	Description
Sink<T, ChannelReader<T>>

Type Parameters

Name	Description
T

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Combine<TIn, TOut, TMat>(Func<int, IGraph<UniformFanOutShape<TIn, TOut>, TMat>>, Sink<TOut, NotUsed>, Sink<TOut, NotUsed>, params Sink<TOut, NotUsed>[])

Combine several sinks with fan-out strategy like Broadcast<T> or Balance<T> and returns Sink<TIn, TMat>.

Declaration

public static Sink<TIn, NotUsed> Combine<TIn, TOut, TMat>(Func<int, IGraph<UniformFanOutShape<TIn, TOut>, TMat>> strategy, Sink<TOut, NotUsed> first, Sink<TOut, NotUsed> second, params Sink<TOut, NotUsed>[] rest)

Parameters

Type	Name	Description
Func<int, IGraph<UniformFanOutShape<TIn, TOut>, TMat>>	strategy	TBD
Sink<TOut, NotUsed>	first	TBD
Sink<TOut, NotUsed>	second	TBD
Sink<TOut, NotUsed>[]	rest	TBD

Returns

Type	Description
Sink<TIn, NotUsed>	TBD

Type Parameters

Name	Description
TIn	TBD
TOut	TBD
TMat	TBD

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Create<TIn>(ISubscriber<TIn>)

Helper to create Sink<TIn, TMat> from Reactive.Streams.ISubscriber<T>.

Declaration

public static Sink<TIn, object> Create<TIn>(ISubscriber<TIn> subscriber)

Parameters

Type	Name	Description
ISubscriber<TIn>	subscriber	TBD

Returns

Type	Description
Sink<TIn, object>	TBD

Type Parameters

Name	Description
TIn	TBD

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FanoutPublisher<TIn>()

A Sink<TIn, TMat> that materializes into Reactive.Streams.IPublisher<T> that can handle more than one Reactive.Streams.ISubscriber<T>.

Declaration

public static Sink<TIn, IPublisher<TIn>> FanoutPublisher<TIn>()

Returns

Type	Description
Sink<TIn, IPublisher<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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FirstOrDefault<TIn>()

A Sink<TIn, TMat> that materializes into a Task<TResult> of the first value received. If the stream completes before signaling at least a single element, the Task will return default value. If the stream signals an error errors before signaling at least a single element, the Task will be failed with the streams exception.

Declaration

public static Sink<TIn, Task<TIn>> FirstOrDefault<TIn>()

Returns

Type	Description
Sink<TIn, Task<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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First<TIn>()

A Sink<TIn, TMat> that materializes into a Task<TResult> of the first value received. If the stream completes before signaling at least a single element, the Task will be failed with a NoSuchElementException. If the stream signals an error before signaling at least a single element, the Task will be failed with the streams exception.

Declaration

public static Sink<TIn, Task<TIn>> First<TIn>()

Returns

Type	Description
Sink<TIn, Task<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

Exceptions

Type	Condition
InvalidOperationException	TBD

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ForEachAsync<TIn>(int, Func<TIn, Task>)

A Sink<TIn, TMat> that will invoke the given async action for each received element. The sink is materialized into a Task will be completed with success when reaching the normal end of the stream, or completed with a failure if there is a failure signaled in the stream.

Declaration

public static Sink<TIn, Task<Done>> ForEachAsync<TIn>(int parallelism, Func<TIn, Task> action)

Parameters

Type	Name	Description
int	parallelism	Number of parallel execution allowed
Func<TIn, Task>	action	Async function delegate to be executed on all elements

Returns

Type	Description
Sink<TIn, Task<Done>>	TBD

Type Parameters

Name	Description
TIn	Input element type

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ForEachParallel<TIn>(int, Action<TIn>)

A Sink<TIn, TMat> that will invoke the given action to each of the elements as they pass in. The sink is materialized into a Task.

If the action throws an exception and the supervision decision is Stop the Task will be completed with failure.

If the action throws an exception and the supervision decision is Resume or Restart the element is dropped and the stream continues.

See also Akka.Streams.Implementation.Fusing.SelectAsyncUnordered<TIn, TOut>

Declaration

[Obsolete("Use `ForEachAsync` instead, it allows you to choose how to run the procedure, by calling some other API returning a Task or using Task.Run. Obsolete since 1.5.2")]
public static Sink<TIn, Task<Done>> ForEachParallel<TIn>(int parallelism, Action<TIn> action)

Parameters

Type	Name	Description
int	parallelism	TBD
Action<TIn>	action	TBD

Returns

Type	Description
Sink<TIn, Task<Done>>	TBD

Type Parameters

Name	Description
TIn	TBD

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ForEach<TIn>(Action<TIn>)

A Sink<TIn, TMat> that will invoke the given action for each received element. The sink is materialized into a Task will be completed with success when reaching the normal end of the stream, or completed with a failure if there is a failure signaled in the stream.

Declaration

public static Sink<TIn, Task<Done>> ForEach<TIn>(Action<TIn> action)

Parameters

Type	Name	Description
Action<TIn>	action	TBD

Returns

Type	Description
Sink<TIn, Task<Done>>	TBD

Type Parameters

Name	Description
TIn	TBD

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FromGraph<TIn, TMat>(IGraph<SinkShape<TIn>, TMat>)

A graph with the shape of a sink logically is a sink, this method makes it so also in type.

Declaration

public static Sink<TIn, TMat> FromGraph<TIn, TMat>(IGraph<SinkShape<TIn>, TMat> graph)

Parameters

Type	Name	Description
IGraph<SinkShape<TIn>, TMat>	graph	TBD

Returns

Type	Description
Sink<TIn, TMat>	TBD

Type Parameters

Name	Description
TIn	TBD
TMat	TBD

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FromSubscriber<TIn>(ISubscriber<TIn>)

Helper to create Sink<TIn, TMat> from Reactive.Streams.ISubscriber<T>.

Declaration

public static Sink<TIn, NotUsed> FromSubscriber<TIn>(ISubscriber<TIn> subscriber)

Parameters

Type	Name	Description
ISubscriber<TIn>	subscriber	TBD

Returns

Type	Description
Sink<TIn, NotUsed>	TBD

Type Parameters

Name	Description
TIn	TBD

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FromWriter<T>(ChannelWriter<T>, bool)

Declaration

public static Sink<T, NotUsed> FromWriter<T>(ChannelWriter<T> writer, bool isOwner)

Parameters

Type	Name	Description
ChannelWriter<T>	writer
bool	isOwner

Returns

Type	Description
Sink<T, NotUsed>

Type Parameters

Name	Description
T

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Ignore<TIn>()

A Sink<TIn, TMat> that will consume the stream and discard the elements.

Declaration

public static Sink<TIn, Task<Done>> Ignore<TIn>()

Returns

Type	Description
Sink<TIn, Task<Done>>	TBD

Type Parameters

Name	Description
TIn	TBD

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LastOrDefault<TIn>()

A Sink<TIn, TMat> that materializes into a Task<TResult> of the last value received. If the stream completes before signaling at least a single element, the Task will be return a default value. If the stream signals an error, the Task will be failed with the stream's exception.

Declaration

public static Sink<TIn, Task<TIn>> LastOrDefault<TIn>()

Returns

Type	Description
Sink<TIn, Task<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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Last<TIn>()

A Sink<TIn, TMat> that materializes into a Task<TResult> of the last value received. If the stream completes before signaling at least a single element, the Task will be failed with a NoSuchElementException. If the stream signals an error, the Task will be failed with the stream's exception.

Declaration

public static Sink<TIn, Task<TIn>> Last<TIn>()

Returns

Type	Description
Sink<TIn, Task<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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LazyInitAsync<TIn, TMat>(Func<Task<Sink<TIn, TMat>>>)

Creates a real Sink<TIn, TMat> upon receiving the first element. Internal Sink<TIn, TMat> will not be created if there are no elements, because of completion or error.

If upstream completes before an element was received then the Task is completed with `default`.

If upstream fails before an element was received, sinkFactory throws an exception, or materialization of the internal sink fails then the Task is completed with the exception.

Otherwise the Task is completed with the materialized value of the internal sink.

Declaration

public static Sink<TIn, Task<Option<TMat>>> LazyInitAsync<TIn, TMat>(Func<Task<Sink<TIn, TMat>>> sinkFactory)

Parameters

Type	Name	Description
Func<Task<Sink<TIn, TMat>>>	sinkFactory	TBD

Returns

Type	Description
Sink<TIn, Task<Option<TMat>>>

Type Parameters

Name	Description
TIn	TBD
TMat	TBD

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LazySink<TIn, TMat>(Func<TIn, Task<Sink<TIn, TMat>>>, Func<TMat>)

Creates a real Sink<TIn, TMat> upon receiving the first element. Internal Sink<TIn, TMat> will not be created if there are no elements, because of completion or error.

If upstream completes before an element was received then the Task is completed with the value created by fallback.

If upstream fails before an element was received, sinkFactory throws an exception, or materialization of the internal sink fails then the Task is completed with the exception.

Otherwise the Task is completed with the materialized value of the internal sink.

Declaration

[Obsolete("Use LazyInitAsync instead. LazyInitAsync no more needs a fallback function and the materialized value more clearly indicates if the internal sink was materialized or not.")]
public static Sink<TIn, Task<TMat>> LazySink<TIn, TMat>(Func<TIn, Task<Sink<TIn, TMat>>> sinkFactory, Func<TMat> fallback)

Parameters

Type	Name	Description
Func<TIn, Task<Sink<TIn, TMat>>>	sinkFactory	TBD
Func<TMat>	fallback	TBD

Returns

Type	Description
Sink<TIn, Task<TMat>>	TBD

Type Parameters

Name	Description
TIn	TBD
TMat	TBD

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OnComplete<TIn>(Action, Action<Exception>)

A Sink<TIn, TMat> that when the flow is completed, either through a failure or normal completion, apply the provided function with success or failure.

Declaration

public static Sink<TIn, NotUsed> OnComplete<TIn>(Action success, Action<Exception> failure)

Parameters

Type	Name	Description
Action	success	TBD
Action<Exception>	failure	TBD

Returns

Type	Description
Sink<TIn, NotUsed>	TBD

Type Parameters

Name	Description
TIn	TBD

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Publisher<TIn>()

A Sink<TIn, TMat> that materializes into a Reactive.Streams.IPublisher<T>. that can handle one Reactive.Streams.ISubscriber<T>.

Declaration

public static Sink<TIn, IPublisher<TIn>> Publisher<TIn>()

Returns

Type	Description
Sink<TIn, IPublisher<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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Queue<TIn>()

Creates a Sink<TIn, TMat> that is materialized as an ISinkQueue<T>. PullAsync() method is pulling element from the stream and returns Task<TResult>. Task completes when element is available.

Before calling the pull method a second time you need to wait until previous future completes. Pull returns failed future with IllegalStateException if previous future has not yet completed.

Sink<TIn, TMat> will request at most number of elements equal to size of inputBuffer from upstream and then stop back pressure. You can configure size of input by using WithAttributes method.

For stream completion you need to pull all elements from ISinkQueue<T> including last None as completion marker.

Declaration

public static Sink<TIn, ISinkQueue<TIn>> Queue<TIn>()

Returns

Type	Description
Sink<TIn, ISinkQueue<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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Seq<TIn>()

A Sink<TIn, TMat> that keeps on collecting incoming elements until upstream terminates. As upstream may be unbounded, Flow.Create{T}().Take or the stricter Flow.Create{T}().Limit (and their variants) may be used to ensure boundedness. Materializes into a Task of Seq<TIn>() containing all the collected elements. Seq is limited to MaxValue elements, this Sink will cancel the stream after having received that many elements.

Declaration

public static Sink<TIn, Task<IImmutableList<TIn>>> Seq<TIn>()

Returns

Type	Description
Sink<TIn, Task<IImmutableList<TIn>>>	TBD

Type Parameters

Name	Description
TIn	TBD

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Shape<T>(string)

TBD

Declaration

public static SinkShape<T> Shape<T>(string name)

Parameters

Type	Name	Description
string	name	TBD

Returns

Type	Description
SinkShape<T>	TBD

Type Parameters

Name	Description
T	TBD

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Sum<TIn>(Func<TIn, TIn, TIn>)

A Sink<TIn, TMat> that will invoke the given reduce for every received element, giving it its previous output (from the second element) and the element as input. The returned Task<TResult> will be completed with value of the final function evaluation when the input stream ends, or completed with `Failure` if there is a failure signaled in the stream.

If the stream is empty (i.e. completes before signaling any elements), the sum stage will fail its downstream with a NoSuchElementException, which is semantically in-line with that standard library collections do in such situations.

Adheres to the ActorAttributes.SupervisionStrategy attribute.

Declaration

public static Sink<TIn, Task<TIn>> Sum<TIn>(Func<TIn, TIn, TIn> reduce)

Parameters

Type	Name	Description
Func<TIn, TIn, TIn>	reduce	TBD

Returns

Type	Description
Sink<TIn, Task<TIn>>	TBD

Type Parameters

Name	Description
TIn	TBD

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Wrap<TIn, TMat>(IGraph<SinkShape<TIn>, TMat>)

A graph with the shape of a sink logically is a sink, this method makes it so also in type.

Declaration

public static Sink<TIn, TMat> Wrap<TIn, TMat>(IGraph<SinkShape<TIn>, TMat> graph)

Parameters

Type	Name	Description
IGraph<SinkShape<TIn>, TMat>	graph	TBD

Returns

Type	Description
Sink<TIn, TMat>	TBD

Type Parameters

Name	Description
TIn	TBD
TMat	TBD