Prepend the given SourceTOut, TMat to this IFlowTOut, TMat, meaning that before elements are generated from this IFlowTOut, TMat, the Source's elements will be produced until it is exhausted, at which point Flow elements will start being produced. Note that this IFlowTOut, TMat will be materialized together with the SourceTOut, TMat and just kept from producing elements by asserting back-pressure until its time comes. If the given SourceTOut, TMat gets upstream error - no elements from this IFlowTOut, TMat will be pulled. Emits when element is available from the given SourceTOut, TMat or from current stream when the SourceTOut, TMat is completed Backpressures when downstream backpressures Completes when this IFlowTOut, TMat completes Cancels when downstream cancels

public static Source<TOut2, TMat> Prepend<TOut1, TOut2, TMat>(
	this Source<TOut1, TMat> flow,
	IGraph<SourceShape<TOut2>, TMat> that
)
where TOut1 : TOut2

[<ExtensionAttribute>]
static member Prepend : 
        flow : Source<'TOut1, 'TMat> * 
        that : IGraph<SourceShape<'TOut2>, 'TMat> -> Source<'TOut2, 'TMat>  when 'TOut1 : 'TOut2