code: @Override
    public void toSink(Sink<R> sink) {
      checkNotNull(sink, "sink cannot be null");
  
      SinkStreamlet<R> sinkStreamlet = new SinkStreamlet<>(this, sink);
      addChild(sinkStreamlet);
    }
docs: Uses the sink to consume every element of this streamlet
  @param sink The Sink that consumes