Is it possible to write Quake's fast InvSqrt() function in C#?

float InvSqrt (float x)
{
   float xhalf = 0.5f*x;
   int i = *(int*)&x;
   i = 0x5f3759df - (i>>1);
   x = *(float*)&i;
   x = x*(1.5f - xhalf*x*x);
   return x;
}

Input: 79.67
BitConverter Method: 00:00:01.2809018 (0.1120187)
Union Method: 00:00:00.6838758 (0.1120187)
Unsafe Method: 00:00:00.3376401 (0.1120187)

Math.Pow(x, -0.5): 00:00:01.7133228 (0.112034710535584)
1 / Math.Sqrt(x): 00:00:00.3757084 (0.1120347)

[StructLayout(LayoutKind.Explicit, Size=4)]
private struct IntFloat {
    [FieldOffset(0)]
    public float floatValue;

    [FieldOffset(0)]
    public int intValue;

    // redundant assignment to avoid any complaints about uninitialized members
    IntFloat(int x) {
        floatValue = 0;
        intValue = x;
    }

    IntFloat(float x) {
        intValue = 0;
        floatValue = x;
    }

    public static explicit operator float (IntFloat x) {
        return x.floatValue;
    }

    public static explicit operator int (IntFloat x) {
        return x.intValue;
    }

    public static explicit operator IntFloat (int i) {
        return new IntFloat(i);
    }
    public static explicit operator IntFloat (float f) {
        return new IntFloat(f);
    }
}

float InvSqrt(float x)
{
    float xhalf = 0.5f * x;
    int i = BitConverter.ToInt32(BitConverter.GetBytes(x), 0);
    i = 0x5f3759df - (i >> 1);
    x = BitConverter.ToSingle(BitConverter.GetBytes(i), 0);
    x = x * (1.5f - xhalf * x * x);
    return x;
}

unsafe float InvSqrt(float x) { ... }