为什么需要将方法强制转换为“Action”或“Func”才能在值元组中使用它?

为什么编译器不能处理这些 x3 x4 作业?

    void X()
    {
        (Func<int, int>, int) x1 = (GetX, 1);           // OK
        object x2 = x1;                                 // OK
        object x3 = (GetX, 1);                          // Error CS8135 Tuple with 2 elements cannot be converted to type 'object'.
        object x4 = (GetX, 1) as (Func<int, int>, int); // Error CS8307 The first operand of an 'as' operator may not be a tuple literal without a natural type.
        object x5 = ((Func<int, int>, int))(GetX, 1);   // OK
        object x6 = ((Func<int, int>)GetX, 1);          // OK
    }

    int GetX(int x)
    {
        return x;
    }