It looks cool on [MSDN](http://msdn.microsoft.com/en-us/library/system.runtime.compilerservices.methodimploptions%28v=VS.100%29.aspx):

> 
> Specifies that the method is declared, but its implementation is
>  provided elsewhere.
> 
> 
> 

So I tried it in a console application:

```
public class Program
{
    [MethodImplAttribute(MethodImplOptions.ForwardRef)]
    public static extern void Invoke();

    static void Main(string[] args)
    {
        Invoke();
        Console.Read();
    }
}

```

Then what should I do now? Where can I provide the implementation of `Program.Invoke`?