docs: public <L, R> SingleOutputStreamOperator<R> flatSelect(
  			final OutputTag<L> timedOutPartialMatchesTag,
  			final PatternFlatTimeoutFunction<T, L> patternFlatTimeoutFunction,
  			final TypeInformation<R> outTypeInfo,
  			final PatternFlatSelectFunction<T, R> patternFlatSelectFunction) {
  
  		final PatternProcessFunction<T, R> processFunction =
  			fromFlatSelect(builder.clean(patternFlatSelectFunction))
  				.withTimeoutHandler(timedOutPartialMatchesTag, builder.clean(patternFlatTimeoutFunction))
  				.build();
  
  		return process(processFunction, outTypeInfo);
  	}