code: @PublicEvolving
  	public CassandraSink<IN> uid(String uid) {
  		if (useDataStreamSink) {
  			getSinkTransformation().setUid(uid);
  		} else {
  			getStreamTransformation().setUid(uid);
  		}
  		return this;
  	}
docs: Sets an ID for this operator.
  
  <p>The specified ID is used to assign the same operator ID across job
  submissions (for example when starting a job from a savepoint).
  
  <p><strong>Important</strong>: this ID needs to be unique per
  transformation and job. Otherwise, job submission will fail.
  
  @param uid The unique user-specified ID of this transformation.
  @return The operator with the specified ID.