public static <T> AppendingFactoryExpression<T> appending(Expression<T> base, Expression<?>... rest) {
        return new AppendingFactoryExpression<T>(base, rest);
    }
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
querydsl-core/src/main/java/com/querydsl/core/types/Projections.java