We ensure we only produce one MemberTracker for each member which logically lives on the declaring type. So for example if you get a member from a derived class which is declared on the base class it should be the same as getting the member from the base class. That’s easy enough until you get into extension members – here there might be one extension member which is being applied to multiple types. Therefore we need to take into account the extension type when ensuring that we only have 1 MemberTracker ever created.
