code: @PublicEvolving
  	public DataStreamSink<T> printToErr() {
  		PrintSinkFunction<T> printFunction = new PrintSinkFunction<>(true);
  		return addSink(printFunction).name("Print to Std. Err");
  	}
docs: Writes a DataStream to the standard output stream (stderr).
  
  <p>For each element of the DataStream the result of {@link Object#toString()} is written.
  
  <p>NOTE: This will print to stderr on the machine where the code is executed, i.e. the Flink
  worker.
  
  @return The closed DataStream.