code: @PublicEvolving
  	public <R extends Tuple> SingleOutputStreamOperator<R> project(int... fieldIndexes) {
  		return new StreamProjection<>(this, fieldIndexes).projectTupleX();
  	}
docs: Initiates a Project transformation on a {@link Tuple} {@link DataStream}.<br>
  <b>Note: Only Tuple DataStreams can be projected.</b>
  
  <p>The transformation projects each Tuple of the DataSet onto a (sub)set of
  fields.
  
  @param fieldIndexes
  The field indexes of the input tuples that are retained. The
  order of fields in the output tuple corresponds to the order
  of field indexes.
  @return The projected DataStream
  
  @see Tuple
  @see DataStream