From the following code, it declares GetId() as an extern method,
https://referencesource.microsoft.com/#mscorlib/system/appdomain.cs,4682
[System.Security.SecuritySafeCritical] // auto-generated
[ResourceExposure(ResourceScope.None)]
[MethodImplAttribute(MethodImplOptions.InternalCall)]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
internal extern Int32 GetId();
I search the whole project for GetId() but I can't find the implmentation of the GetId() method.
