public abstract IFlow<T2, TMat3> ViaMaterialized<T2, TMat2, TMat3>(
	IGraph<FlowShape<TOut, T2>, TMat2> flow,
	Func<TMat, TMat2, TMat3> combine
)

abstract ViaMaterialized : 
        flow : IGraph<FlowShape<'TOut, 'T2>, 'TMat2> * 
        combine : Func<'TMat, 'TMat2, 'TMat3> -> IFlow<'T2, 'TMat3>