@Override
 public AccumT addInputs(K key, Iterable<InputT> inputs, OldDoFn<?, ?>.ProcessContext c) {
   AccumT accum = keyedCombineFn.createAccumulator(key);
   for (InputT input : inputs) {
     accum = keyedCombineFn.addInput(key, accum, input);
   }
   return accum;
 }
 @Override
 public AccumT createAccumulator(
     K key,
     PipelineOptions options,
     SideInputReader sideInputReader,
     Collection<? extends BoundedWindow> windows) {
   return keyedCombineFn.createAccumulator(key);
 }
 @Override
 public AccumT compact(
     K key,
     AccumT accumulator,
     PipelineOptions options,
     SideInputReader sideInputReader,
     Collection<? extends BoundedWindow> windows) {
   return keyedCombineFn.compact(key, accumulator);
 }
 @Override
 public AccumT mergeAccumulators(
     K key,
     Iterable<AccumT> accumulators,
     PipelineOptions options,
     SideInputReader sideInputReader,
     Collection<? extends BoundedWindow> windows) {
   return keyedCombineFn.mergeAccumulators(key, accumulators);
 }
 @Override
 public OutputT apply(K key, Iterable<? extends InputT> inputs, OldDoFn<?, ?>.ProcessContext c) {
   return keyedCombineFn.apply(key, inputs);
 }
 @Override
 public AccumT compact(K key, AccumT accumulator, OldDoFn<?, ?>.ProcessContext c) {
   return keyedCombineFn.compact(key, accumulator);
 }
 @Override
 public OutputT extractOutput(K key, AccumT accumulator, OldDoFn<?, ?>.ProcessContext c) {
   return keyedCombineFn.extractOutput(key, accumulator);
 }
 @Override
 public AccumT mergeAccumulators(
     K key, Iterable<AccumT> accumulators, OldDoFn<?, ?>.ProcessContext c) {
   return keyedCombineFn.mergeAccumulators(key, accumulators);
 }
 @Override
 public AccumT addInput(
     K key, AccumT accumulator, InputT input, OldDoFn<?, ?>.ProcessContext c) {
   return keyedCombineFn.addInput(key, accumulator, input);
 }
 @Override
 public AccumT createAccumulator(K key, OldDoFn<?, ?>.ProcessContext c) {
   return keyedCombineFn.createAccumulator(key);
 }
 @Override
 public String toString() {
   return keyedCombineFn.toString();
 }