/// <summary>
/// Converts this Flow to a <see cref="IRunnableGraph{TMat}"/> that materializes to a Reactive Streams <see cref="IProcessor{T1,T2}"/>
/// which implements the operations encapsulated by this Flow. Every materialization results in a new Processor
/// instance, i.e. the returned <see cref="IRunnableGraph{TMat}"/> is reusable.
/// </summary>
/// <returns>A <see cref="IRunnableGraph{TMat}"/> that materializes to a <see cref="IProcessor{T1,T2}"/> when Run() is called on it.</returns>
public IRunnableGraph <IProcessor <TIn, TOut> > ToProcessor()
=> Source.AsSubscriber <TIn>()
.Via(this)
.ToMaterialized(Sink.AsPublisher <TOut>(false), Keep.Both)
.MapMaterializedValue(t => new FlowProcessor <TIn, TOut>(t.Item1, t.Item2) as IProcessor <TIn, TOut>);
/// <summary>
/// Materializes this Source immediately.
/// </summary>
/// <param name="materializer">The materializer.</param>
/// <returns>A tuple containing the (1) materialized value and (2) a new <see cref="Source"/>
/// that can be used to consume elements from the newly materialized <see cref="Source"/>.</returns>
public Tuple <TMat, Source <TOut, NotUsed> > PreMaterialize(IMaterializer materializer)
{
var tup = ToMaterialized(Sink.AsPublisher <TOut>(fanout: true), Keep.Both).Run(materializer);
return(Tuple.Create(tup.Item1, Source.FromPublisher(tup.Item2)));
}