code: public static <T> AppendingFactoryExpression<T> appending(Expression<T> base, Expression<?>... rest) {
          return new AppendingFactoryExpression<T>(base, rest);
      }
docs: Create an appending factory expression which serializes all the arguments but the uses
  the base value as the return value
  
  @param base first argument
  @param rest additional arguments
  @param <T> type of projection
  @return factory expression