code: @Deprecated
  	@Override
  	@Internal
  	public <R> SingleOutputStreamOperator<R> process(
  			ProcessFunction<T, R> processFunction,
  			TypeInformation<R> outputType) {
  
  		LegacyKeyedProcessOperator<KEY, T, R> operator = new LegacyKeyedProcessOperator<>(clean(processFunction));
  
  		return transform("Process", outputType, operator);
  	}
docs: Applies the given {@link ProcessFunction} on the input stream, thereby creating a transformed output stream.
  
  <p>The function will be called for every element in the input streams and can produce zero
  or more output elements. Contrary to the {@link DataStream#flatMap(FlatMapFunction)}
  function, this function can also query the time and set timers. When reacting to the firing
  of set timers the function can directly emit elements and/or register yet more timers.
  
  @param processFunction The {@link ProcessFunction} that is called for each element
  in the stream.
  @param outputType {@link TypeInformation} for the result type of the function.
  
  @param <R> The type of elements emitted by the {@code ProcessFunction}.
  
  @return The transformed {@link DataStream}.
  
  @deprecated Use {@link KeyedStream#process(KeyedProcessFunction, TypeInformation)}