code: public <T0, T1> SingleOutputStreamOperator<Tuple2<T0, T1>> projectTuple2() {
  		TypeInformation<?>[] fTypes = extractFieldTypes(fieldIndexes, dataStream.getType());
  		TupleTypeInfo<Tuple2<T0, T1>> tType = new TupleTypeInfo<Tuple2<T0, T1>>(fTypes);
  
  		return dataStream.transform("Projection", tType, new StreamProject<IN, Tuple2<T0, T1>>(fieldIndexes, tType.createSerializer(dataStream.getExecutionConfig())));
  	}
docs: Projects a {@link Tuple} {@link DataStream} to the previously selected fields.
  
  @return The projected DataStream.
  @see Tuple
  @see DataStream