private DiscreteCellSink(DiscreteCellStreamSink <T> streamSink, Cell <T> cell)
: base(cell) => this.StreamSink = streamSink;
private DiscreteCellSink(DiscreteCellStreamSink <T> streamSink, T initialValue)
: this(streamSink, new Cell <T>(streamSink, initialValue))
{
}