class MapElements extends Operator<OutputT> implements CompositeOperator<InputT, OutputT>, TypeAware.Output<OutputT> {

  public static <InputT> UsingBuilder<InputT> of(PCollection<InputT> input) {
    return named(null).of(input);
  }

  private  MapElements(
      @Nullable String name,
      UnaryFunctionEnv<InputT, OutputT> mapper,
      @Nullable TypeDescriptor<OutputT> outputType);

}