MoreLinq -如何在不从选择器获取空值的情况下执行FullJoin？

using System;
using MoreLinq;

public class Program
{
    public static void Main()
    {
        var numbers1 = new[] { 1, 2, 3, 4, 5 };
        var numbers2 = new[] { 4, 5, 6, 7, 8 };

        var result = numbers1.FullJoin(numbers2,
            x => x,
            y => y,
            (x, y) => new { Value1 = x, Value2 = y },
            new { Value1 = 0, Value2 = 0 });

        foreach (var item in result)
        {
            Console.WriteLine($"Value1: {item.Value1}, Value2: {item.Value2}");
        }
    }
}

Value1: 1, Value2: 0
Value1: 2, Value2: 0
Value1: 3, Value2: 0
Value1: 4, Value2: 4
Value1: 5, Value2: 5
Value1: 0, Value2: 6
Value1: 0, Value2: 7
Value1: 0, Value2: 8