code: @Override
  	protected void computeOperatorSpecificDefaultEstimates(DataStatistics statistics) {
  		this.estimatedNumRecords = getPredecessorNode().getEstimatedNumRecords();
  		this.estimatedOutputSize = getPredecessorNode().getEstimatedOutputSize();
  	}
docs: Computes the estimated outputs for the data sink. Since the sink does not modify anything, it simply
  copies the output estimates from its direct predecessor.