How is "Make Object ID" implemented in the .NET debugger?

I would like know how this feature is implemented in VS - I understand it holds some sort of weak-reference to the object in the debugged-application's memory, but how exactly is it accomplished?

I know simply trackin开发者_开发问答g the address (as in native code) wouldn't work, because the GC might move the object about, invalidating the address.

Thanks.

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A description of it can be found here. It uses an unmanaged api.