code: @PublicEvolving
  	public DataStreamSink<T> writeAsCsv(String path, WriteMode writeMode) {
  		return writeAsCsv(path, writeMode, CsvOutputFormat.DEFAULT_LINE_DELIMITER, CsvOutputFormat.DEFAULT_FIELD_DELIMITER);
  	}
docs: Writes a DataStream to the file specified by the path parameter.
  
  <p>For every field of an element of the DataStream the result of {@link Object#toString()}
  is written. This method can only be used on data streams of tuples.
  
  @param path
  the path pointing to the location the text file is written to
  @param writeMode
  Controls the behavior for existing files. Options are
  NO_OVERWRITE and OVERWRITE.
  
  @return the closed DataStream