Create a source that will unfold a value of type TState by passing it through a flow. The flow should emit a pair of the next state TState and output elements of type TOut. Source completes when the flow completes.

The timeout parameter specifies waiting time after inner flow provided by the user for unfold flow API cancels upstream, to get also the downstream cancelation (as graceful completion or failure which is propagated). If inner flow fails to complete/fail downstream, stage is failed.

IMPORTANT CAVEAT: The given flow must not change the number of elements passing through it(i.e.it should output exactly one element for every received element). Ignoring this, will have an unpredicted result, and may result in a deadlock.

Declaration

public static Source<TOut, TMat> UnfoldFlow<TState, TOut, TMat>(TState seed, IGraph<FlowShape<TState, (TState, TOut)>, TMat> flow, TimeSpan timeout)

Parameters

Type	Name	Description
TState	seed	intial state
IGraph<FlowShape<TState, System.ValueTuple<TState, TOut>>, TMat>	flow	flow, through which value is passed
TimeSpan	timeout	timeout

Returns

Type	Description
Source<TOut, TMat>

Type Parameters

Name	Description
TState	state type
TOut	output elements type
TMat	materialized value type

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UnfoldFlowWith<TOut, TState, TFlowOut, TMat>(TState, IGraph<FlowShape<TState, TFlowOut>, TMat>, Func<TFlowOut, Option<(TState, TOut)>>, TimeSpan)

EXPERIMENTAL API

Create a source that will unfold a value of type TState by passing it through a flow. The flow should emit an output value of type TFlowOut, that when fed to the unfolding function, generates a pair of the next state TState and output elements of type TOut.

The timeout parameter specifies waiting time after inner flow provided by the user for unfold flow API cancels upstream, to get also the downstream cancelation(as graceful completion or failure which is propagated). If inner flow fails to complete/fail downstream, stage is failed.

Declaration

public static Source<TOut, TMat> UnfoldFlowWith<TOut, TState, TFlowOut, TMat>(TState seed, IGraph<FlowShape<TState, TFlowOut>, TMat> flow, Func<TFlowOut, Option<(TState, TOut)>> unfoldWith, TimeSpan timeout)

Parameters

Type	Name	Description
TState	seed	intial state
IGraph<FlowShape<TState, TFlowOut>, TMat>	flow	flow through which value is passed
Func<TFlowOut, Option<System.ValueTuple<TState, TOut>>>	unfoldWith	unfolding function
TimeSpan	timeout	timeout

Returns

Type	Description
Source<TOut, TMat>

Type Parameters

Name	Description
TOut	output elements type
TState	state type
TFlowOut	flow output value type
TMat	materialized value type