/// <summary>
 /// Adds the given sink to this DataStream. Only streams with sinks added will be executed once the <see cref="StreamContextEnvironment.Execute()"/> method is called.
 /// </summary>
 /// <param name="sinkFunction">The object containing the sink's invoke function.</param>
 /// <returns>The closed DataStream.</returns>
 public DataStreamSink <TElement> AddSink(ISinkFunction <TElement> sinkFunction)
 {
     return(null);
 }
 public StreamSink(ISinkFunction <TInput> userFunction) : base(userFunction)
 {
 }